5th Workshop on the Scientific Cooperation between German Research Centres and JINR
The PAX ProjectThe PAX ProjectSpin Physics at GSISpin Physics at GSI
Spokespersons
Paolo Lenisa Ferrara University lenisamaildesyde
Frank Rathmann FZ-Juumllich frathmannfz-juelichde
Polarized Antiproton Experimentswwwfz-juelichdeikppax
Central Physics IssueCentral Physics Issue
Transversity distribution of the nucleon
ndash last leading-twist missing piece of the QCD description of the partonic structure of the nucleon
ndash directly accessible uniquely via the double transverse spin asymmetry ATT in the Drell-Yan production of lepton pairs
ndash theoretical expectations for ATT in DY 30-40 bull transversely polarized antiprotons bull transversely polarized proton target
ndash definitive observation of h1q
(xQ2) of the proton for the valence quarks
Leading Twist Distribution Functions Leading Twist Distribution Functions
12 12
L L
+f1(x)
h1(x)
proton
protonrsquo
quark
quarkrsquo
u = 12(uR + uL)u = 12(uR - uL)
No probabilistic interpretation in the helicity base (off diagonal)
Probabilistic interpretation in helicity base
q(x) spin averaged
(well known)
q(x) helicity diff(known)
q(x) helicity flip(unknown)
12 12
R R
12 12
L L
-12 12
R R
g1(x)
Transversitybase
12 -12
R L
-
Evaluation by Evaluation by QCD Program Advisory Committee (July QCD Program Advisory Committee (July
2004)2004)STI ReportYour LoI has convinced the QCD-PAC
a)that Polarization must be included into the design of FAIR from the beginning and
b)that the presently proposed scheme is not optimized as to the physics You [hellip] are invited and encouraged to design a world-class facility with unequalled degree of polarization of antiprotons
Common Report
[hellip] The PAC considers the spin physics of extreme interest and the building of an antiproton polarized beam as a unique possibility for the FAIR Project
[hellip] The unique physics opportunities made possible with polarized antiproton beams andor polarized target are extremely exciting especially in double spin measurements
[hellip] It would be very unfortunate if decisions about the facility made now later preclude the science
1 10 100 T (MeV)
σEM
|| (
mb
)
100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Exploitation of Spin TransferExploitation of Spin Transfer
epep PAX will employ spin-
transfer from polarized electrons of the target to
antiprotonsHydrogen gas target ①+② in strong field (300 mT)
Pe=0993Pz=0007
(QED Process calculable)
01
02
03
04B
eam
Pola
riza
tion
P(2
middotτbeam)
10 T (MeV)100
EM only
5
10
30
20
40
Ψacc=50 mrad
0
1
Filter Test T = 23 MeV Ψacc= 44 mrad
Buildup in HESR (800 MeV)
F Rathmann et al PRL 94 014801 (2005)
Antiproton Beam PolarizationAntiproton Beam Polarization
Transversity in Drell-Yan processesTransversity in Drell-Yan processes
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
AATTTT for PAX kinematic conditions for PAX kinematic conditions
RHIC τ=x1x2=M2s~10-3 rarr Exploration of the sea quark content (polarizations small) ATT very small (~ 1 )
TT
TT
a
A
T=22 GeV (s=67 GeV)
T=15 GeV(s=57 GeV)
Anselmino et al PLB 59497
(2004)
010
015
025
03
xF=x1-x2
02 04 060
ATTaTT gt 03Models predict |h1
u|gtgt|h1d|
)Mx(u)Mx(u
)Mx(h)Mx(haA
21
21
21
u1
21
u1
TTTT
)qqqwhere( pp
Main contribution to Drell-Yan events at PAX from x1~x2~τdeduction of x-dependence of h1
u(xM2)
PAX M2~10 GeV2 s~30-50 GeV2 τ=x1x2=M2s~02-03
rarr Exploration of valence quarks (h1q(xQ2) large)
Similar predictions by Efremov et al
Eur Phys J C35 207 (2004)
xF=x1-x2
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR (COSY-like) at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons(also fixed target experiments possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Central Physics IssueCentral Physics Issue
Transversity distribution of the nucleon
ndash last leading-twist missing piece of the QCD description of the partonic structure of the nucleon
ndash directly accessible uniquely via the double transverse spin asymmetry ATT in the Drell-Yan production of lepton pairs
ndash theoretical expectations for ATT in DY 30-40 bull transversely polarized antiprotons bull transversely polarized proton target
ndash definitive observation of h1q
(xQ2) of the proton for the valence quarks
Leading Twist Distribution Functions Leading Twist Distribution Functions
12 12
L L
+f1(x)
h1(x)
proton
protonrsquo
quark
quarkrsquo
u = 12(uR + uL)u = 12(uR - uL)
No probabilistic interpretation in the helicity base (off diagonal)
Probabilistic interpretation in helicity base
q(x) spin averaged
(well known)
q(x) helicity diff(known)
q(x) helicity flip(unknown)
12 12
R R
12 12
L L
-12 12
R R
g1(x)
Transversitybase
12 -12
R L
-
Evaluation by Evaluation by QCD Program Advisory Committee (July QCD Program Advisory Committee (July
2004)2004)STI ReportYour LoI has convinced the QCD-PAC
a)that Polarization must be included into the design of FAIR from the beginning and
b)that the presently proposed scheme is not optimized as to the physics You [hellip] are invited and encouraged to design a world-class facility with unequalled degree of polarization of antiprotons
Common Report
[hellip] The PAC considers the spin physics of extreme interest and the building of an antiproton polarized beam as a unique possibility for the FAIR Project
[hellip] The unique physics opportunities made possible with polarized antiproton beams andor polarized target are extremely exciting especially in double spin measurements
[hellip] It would be very unfortunate if decisions about the facility made now later preclude the science
1 10 100 T (MeV)
σEM
|| (
mb
)
100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Exploitation of Spin TransferExploitation of Spin Transfer
epep PAX will employ spin-
transfer from polarized electrons of the target to
antiprotonsHydrogen gas target ①+② in strong field (300 mT)
Pe=0993Pz=0007
(QED Process calculable)
01
02
03
04B
eam
Pola
riza
tion
P(2
middotτbeam)
10 T (MeV)100
EM only
5
10
30
20
40
Ψacc=50 mrad
0
1
Filter Test T = 23 MeV Ψacc= 44 mrad
Buildup in HESR (800 MeV)
F Rathmann et al PRL 94 014801 (2005)
Antiproton Beam PolarizationAntiproton Beam Polarization
Transversity in Drell-Yan processesTransversity in Drell-Yan processes
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
AATTTT for PAX kinematic conditions for PAX kinematic conditions
RHIC τ=x1x2=M2s~10-3 rarr Exploration of the sea quark content (polarizations small) ATT very small (~ 1 )
TT
TT
a
A
T=22 GeV (s=67 GeV)
T=15 GeV(s=57 GeV)
Anselmino et al PLB 59497
(2004)
010
015
025
03
xF=x1-x2
02 04 060
ATTaTT gt 03Models predict |h1
u|gtgt|h1d|
)Mx(u)Mx(u
)Mx(h)Mx(haA
21
21
21
u1
21
u1
TTTT
)qqqwhere( pp
Main contribution to Drell-Yan events at PAX from x1~x2~τdeduction of x-dependence of h1
u(xM2)
PAX M2~10 GeV2 s~30-50 GeV2 τ=x1x2=M2s~02-03
rarr Exploration of valence quarks (h1q(xQ2) large)
Similar predictions by Efremov et al
Eur Phys J C35 207 (2004)
xF=x1-x2
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR (COSY-like) at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons(also fixed target experiments possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Leading Twist Distribution Functions Leading Twist Distribution Functions
12 12
L L
+f1(x)
h1(x)
proton
protonrsquo
quark
quarkrsquo
u = 12(uR + uL)u = 12(uR - uL)
No probabilistic interpretation in the helicity base (off diagonal)
Probabilistic interpretation in helicity base
q(x) spin averaged
(well known)
q(x) helicity diff(known)
q(x) helicity flip(unknown)
12 12
R R
12 12
L L
-12 12
R R
g1(x)
Transversitybase
12 -12
R L
-
Evaluation by Evaluation by QCD Program Advisory Committee (July QCD Program Advisory Committee (July
2004)2004)STI ReportYour LoI has convinced the QCD-PAC
a)that Polarization must be included into the design of FAIR from the beginning and
b)that the presently proposed scheme is not optimized as to the physics You [hellip] are invited and encouraged to design a world-class facility with unequalled degree of polarization of antiprotons
Common Report
[hellip] The PAC considers the spin physics of extreme interest and the building of an antiproton polarized beam as a unique possibility for the FAIR Project
[hellip] The unique physics opportunities made possible with polarized antiproton beams andor polarized target are extremely exciting especially in double spin measurements
[hellip] It would be very unfortunate if decisions about the facility made now later preclude the science
1 10 100 T (MeV)
σEM
|| (
mb
)
100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Exploitation of Spin TransferExploitation of Spin Transfer
epep PAX will employ spin-
transfer from polarized electrons of the target to
antiprotonsHydrogen gas target ①+② in strong field (300 mT)
Pe=0993Pz=0007
(QED Process calculable)
01
02
03
04B
eam
Pola
riza
tion
P(2
middotτbeam)
10 T (MeV)100
EM only
5
10
30
20
40
Ψacc=50 mrad
0
1
Filter Test T = 23 MeV Ψacc= 44 mrad
Buildup in HESR (800 MeV)
F Rathmann et al PRL 94 014801 (2005)
Antiproton Beam PolarizationAntiproton Beam Polarization
Transversity in Drell-Yan processesTransversity in Drell-Yan processes
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
AATTTT for PAX kinematic conditions for PAX kinematic conditions
RHIC τ=x1x2=M2s~10-3 rarr Exploration of the sea quark content (polarizations small) ATT very small (~ 1 )
TT
TT
a
A
T=22 GeV (s=67 GeV)
T=15 GeV(s=57 GeV)
Anselmino et al PLB 59497
(2004)
010
015
025
03
xF=x1-x2
02 04 060
ATTaTT gt 03Models predict |h1
u|gtgt|h1d|
)Mx(u)Mx(u
)Mx(h)Mx(haA
21
21
21
u1
21
u1
TTTT
)qqqwhere( pp
Main contribution to Drell-Yan events at PAX from x1~x2~τdeduction of x-dependence of h1
u(xM2)
PAX M2~10 GeV2 s~30-50 GeV2 τ=x1x2=M2s~02-03
rarr Exploration of valence quarks (h1q(xQ2) large)
Similar predictions by Efremov et al
Eur Phys J C35 207 (2004)
xF=x1-x2
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR (COSY-like) at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons(also fixed target experiments possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Evaluation by Evaluation by QCD Program Advisory Committee (July QCD Program Advisory Committee (July
2004)2004)STI ReportYour LoI has convinced the QCD-PAC
a)that Polarization must be included into the design of FAIR from the beginning and
b)that the presently proposed scheme is not optimized as to the physics You [hellip] are invited and encouraged to design a world-class facility with unequalled degree of polarization of antiprotons
Common Report
[hellip] The PAC considers the spin physics of extreme interest and the building of an antiproton polarized beam as a unique possibility for the FAIR Project
[hellip] The unique physics opportunities made possible with polarized antiproton beams andor polarized target are extremely exciting especially in double spin measurements
[hellip] It would be very unfortunate if decisions about the facility made now later preclude the science
1 10 100 T (MeV)
σEM
|| (
mb
)
100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Exploitation of Spin TransferExploitation of Spin Transfer
epep PAX will employ spin-
transfer from polarized electrons of the target to
antiprotonsHydrogen gas target ①+② in strong field (300 mT)
Pe=0993Pz=0007
(QED Process calculable)
01
02
03
04B
eam
Pola
riza
tion
P(2
middotτbeam)
10 T (MeV)100
EM only
5
10
30
20
40
Ψacc=50 mrad
0
1
Filter Test T = 23 MeV Ψacc= 44 mrad
Buildup in HESR (800 MeV)
F Rathmann et al PRL 94 014801 (2005)
Antiproton Beam PolarizationAntiproton Beam Polarization
Transversity in Drell-Yan processesTransversity in Drell-Yan processes
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
AATTTT for PAX kinematic conditions for PAX kinematic conditions
RHIC τ=x1x2=M2s~10-3 rarr Exploration of the sea quark content (polarizations small) ATT very small (~ 1 )
TT
TT
a
A
T=22 GeV (s=67 GeV)
T=15 GeV(s=57 GeV)
Anselmino et al PLB 59497
(2004)
010
015
025
03
xF=x1-x2
02 04 060
ATTaTT gt 03Models predict |h1
u|gtgt|h1d|
)Mx(u)Mx(u
)Mx(h)Mx(haA
21
21
21
u1
21
u1
TTTT
)qqqwhere( pp
Main contribution to Drell-Yan events at PAX from x1~x2~τdeduction of x-dependence of h1
u(xM2)
PAX M2~10 GeV2 s~30-50 GeV2 τ=x1x2=M2s~02-03
rarr Exploration of valence quarks (h1q(xQ2) large)
Similar predictions by Efremov et al
Eur Phys J C35 207 (2004)
xF=x1-x2
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR (COSY-like) at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons(also fixed target experiments possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
1 10 100 T (MeV)
σEM
|| (
mb
)
100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Exploitation of Spin TransferExploitation of Spin Transfer
epep PAX will employ spin-
transfer from polarized electrons of the target to
antiprotonsHydrogen gas target ①+② in strong field (300 mT)
Pe=0993Pz=0007
(QED Process calculable)
01
02
03
04B
eam
Pola
riza
tion
P(2
middotτbeam)
10 T (MeV)100
EM only
5
10
30
20
40
Ψacc=50 mrad
0
1
Filter Test T = 23 MeV Ψacc= 44 mrad
Buildup in HESR (800 MeV)
F Rathmann et al PRL 94 014801 (2005)
Antiproton Beam PolarizationAntiproton Beam Polarization
Transversity in Drell-Yan processesTransversity in Drell-Yan processes
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
AATTTT for PAX kinematic conditions for PAX kinematic conditions
RHIC τ=x1x2=M2s~10-3 rarr Exploration of the sea quark content (polarizations small) ATT very small (~ 1 )
TT
TT
a
A
T=22 GeV (s=67 GeV)
T=15 GeV(s=57 GeV)
Anselmino et al PLB 59497
(2004)
010
015
025
03
xF=x1-x2
02 04 060
ATTaTT gt 03Models predict |h1
u|gtgt|h1d|
)Mx(u)Mx(u
)Mx(h)Mx(haA
21
21
21
u1
21
u1
TTTT
)qqqwhere( pp
Main contribution to Drell-Yan events at PAX from x1~x2~τdeduction of x-dependence of h1
u(xM2)
PAX M2~10 GeV2 s~30-50 GeV2 τ=x1x2=M2s~02-03
rarr Exploration of valence quarks (h1q(xQ2) large)
Similar predictions by Efremov et al
Eur Phys J C35 207 (2004)
xF=x1-x2
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR (COSY-like) at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons(also fixed target experiments possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
01
02
03
04B
eam
Pola
riza
tion
P(2
middotτbeam)
10 T (MeV)100
EM only
5
10
30
20
40
Ψacc=50 mrad
0
1
Filter Test T = 23 MeV Ψacc= 44 mrad
Buildup in HESR (800 MeV)
F Rathmann et al PRL 94 014801 (2005)
Antiproton Beam PolarizationAntiproton Beam Polarization
Transversity in Drell-Yan processesTransversity in Drell-Yan processes
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
AATTTT for PAX kinematic conditions for PAX kinematic conditions
RHIC τ=x1x2=M2s~10-3 rarr Exploration of the sea quark content (polarizations small) ATT very small (~ 1 )
TT
TT
a
A
T=22 GeV (s=67 GeV)
T=15 GeV(s=57 GeV)
Anselmino et al PLB 59497
(2004)
010
015
025
03
xF=x1-x2
02 04 060
ATTaTT gt 03Models predict |h1
u|gtgt|h1d|
)Mx(u)Mx(u
)Mx(h)Mx(haA
21
21
21
u1
21
u1
TTTT
)qqqwhere( pp
Main contribution to Drell-Yan events at PAX from x1~x2~τdeduction of x-dependence of h1
u(xM2)
PAX M2~10 GeV2 s~30-50 GeV2 τ=x1x2=M2s~02-03
rarr Exploration of valence quarks (h1q(xQ2) large)
Similar predictions by Efremov et al
Eur Phys J C35 207 (2004)
xF=x1-x2
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR (COSY-like) at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons(also fixed target experiments possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Transversity in Drell-Yan processesTransversity in Drell-Yan processes
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
AATTTT for PAX kinematic conditions for PAX kinematic conditions
RHIC τ=x1x2=M2s~10-3 rarr Exploration of the sea quark content (polarizations small) ATT very small (~ 1 )
TT
TT
a
A
T=22 GeV (s=67 GeV)
T=15 GeV(s=57 GeV)
Anselmino et al PLB 59497
(2004)
010
015
025
03
xF=x1-x2
02 04 060
ATTaTT gt 03Models predict |h1
u|gtgt|h1d|
)Mx(u)Mx(u
)Mx(h)Mx(haA
21
21
21
u1
21
u1
TTTT
)qqqwhere( pp
Main contribution to Drell-Yan events at PAX from x1~x2~τdeduction of x-dependence of h1
u(xM2)
PAX M2~10 GeV2 s~30-50 GeV2 τ=x1x2=M2s~02-03
rarr Exploration of valence quarks (h1q(xQ2) large)
Similar predictions by Efremov et al
Eur Phys J C35 207 (2004)
xF=x1-x2
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR (COSY-like) at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons(also fixed target experiments possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
AATTTT for PAX kinematic conditions for PAX kinematic conditions
RHIC τ=x1x2=M2s~10-3 rarr Exploration of the sea quark content (polarizations small) ATT very small (~ 1 )
TT
TT
a
A
T=22 GeV (s=67 GeV)
T=15 GeV(s=57 GeV)
Anselmino et al PLB 59497
(2004)
010
015
025
03
xF=x1-x2
02 04 060
ATTaTT gt 03Models predict |h1
u|gtgt|h1d|
)Mx(u)Mx(u
)Mx(h)Mx(haA
21
21
21
u1
21
u1
TTTT
)qqqwhere( pp
Main contribution to Drell-Yan events at PAX from x1~x2~τdeduction of x-dependence of h1
u(xM2)
PAX M2~10 GeV2 s~30-50 GeV2 τ=x1x2=M2s~02-03
rarr Exploration of valence quarks (h1q(xQ2) large)
Similar predictions by Efremov et al
Eur Phys J C35 207 (2004)
xF=x1-x2
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR (COSY-like) at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons(also fixed target experiments possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR (COSY-like) at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons(also fixed target experiments possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons (also fixed target experiment possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons(also fixed target experiments possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
I CSR at FAIR (35 GeVc)a Formfactor measurement pp rarr e+e-
- unpolarized antiproton beam on polarized internal targetb CSR + AP pp elastic
II Asymmetric Collider pp 35 GeVc protons + 15 GeVc antiprotons(also fixed target experiments possible)
Towards an Asymmetric Polarized Hadron ColliderTowards an Asymmetric Polarized Hadron Collider
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
AATTTT for PAX kinematic conditions for PAX kinematic conditionsFixed TargetFixed Target vsvs Collider Collider
Anselmino et al PLB 59497 (2004)
22 GeVc
15+35
22 GeVc fixed target
15+35 collider
15 + 15 collider
Collider Options for Transversity measurementbull 15 GeVc + 15 GeVc s=1000 GeV2 too highbull 15 GeVc + 35 GeVc s=220 GeV2 idealideal
Similar predictions by Efremov et al Eur Phys J C35 207
(2004)
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Conceptual Detector DesignConceptual Detector Design
~3 m
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Time scheduleTime schedule
Jan 04 LOI submitted
150604 QCD PAC meeting at GSI
18-190804 Workshop on polarized antiprotons at GSI
150904 Additional PAX document on Polarization at GSIbull F Rathmann et al PRL 94 014801 (2005)
151104 Additional PAX document Number of IPrsquos at HESR211204 Additional PAX document Asymmetric Collider150105 Technical Report (with Milestones)
o Design and Construction of APR at IKP of FZJ
Evaluations amp Green Light for Construction
2005-2008 Technical Design Reports (for Milestones)
gt2012 Commissioning of HESR
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
ConclusionConclusion
Challenging opportunities and new physics accessible at HESR
bullUnique access to a wealth of new fundamental physics observables
bullCentral physics issueCentral physics issue h1q
(xQ2) of the proton in DY processes
bullOther issuesbull Electromagnetic Formfactorsbull Polarization effects in Hard and Soft Scattering processesbull differential cross sections analyzing powers spin correlation
parameters
Asymmetric Collider bull 15 GeVc + 35 GeVc
bull ideal conditions for Transversity measurementsbull Calculation of Intrabeam and Beam-Beam Scattering
(MeshkovSidorin using BETACOOL)
Projections for HESR fed by a dedicated APbull Pbeam gt 030bull 56middot1010 polarized antiprotonsbull Luminosity Fixed target L 27 middot1031 cm-2s-1
Collider L 1030 cm-2s-1 (first estimate)
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Yerevan Physics Institute Yerevan ArmeniaDepartment of Subatomic and Radiation Physics University of Gent Belgium
University of Science amp Technology of China Beijing PR ChinaDepartment of Physics Beijing PR China
Centre de Physique Theorique Ecole Polytechnique Palaiseau FranceHigh Energy Physics Institute Tbilisi State University Tbilisi GeorgiaNuclear Physics Department Tbilisi State University Tbilisi GeorgiaForschungszentrum Juumllich Institut fuumlr Kernphysik Juumllich Germany
Institut fuumlr Theoretische Physik II Ruhr Universitaumlt Bochum GermanyHelmholtz-Institut fuumlr Strahlen- und Kernphysik Bonn GermanyPhysikalisches Institut Universitaumlt Erlangen-Nuumlrnberg Germany
Unternehmensberatung und Service Buumlro (USB) Gerlinde Schulteis amp Partner GbR Langenbernsdorf GermanyDepartment of Mathematics University of Dublin Dublin Ireland
University del Piemonte Orientale and INFN Alessandria ItalyDipartimento di Fisica Universita di Cagliari and INFN Cagliari Italy
Instituto Nationale di Fisica Nucleare Ferrara Italy Dipartimento di Fisica Teorica Universita di Torino and INFN Torino Italy
Instituto Nationale di Fisica Nucleare Frascati ItalyDipartimento di Fisica Universita di Lecce and INFN Lecce Italy
Soltan Institute for Nuclear Studies Warsaw PolandPetersburg Nuclear Physics Institute Gatchina Russia
Institute for Theoretical and Experimental Physics Moscow RussiaLebedev Physical Institute Moscow Russia
Bogoliubov Laboratory of Theoretical Physics Joint Institute for Nuclear Research Dubna RussiaDzhelepov Laboratory of Nuclear Problems Joint Institute for Nuclear Research Dubna Russia
Laboratory of Particle Physics Joint Institute for Nuclear Research Dubna RussiaBudker Institute for Nuclear Physics Novosibirsk Russia
High Energy Physics Institute Protvino RussiaInstitute of Experimental Physics Slovak Academy of Sciences and PJ Safarik University Faculty of Science Kosice Slovakia
Department of Radiation Sciences Nuclear Physics Division Uppsala University Uppsala SwedenCollider Accelerator Department Brookhaven National Laboratory USA
RIKEN BNL Research Center Brookhaven National Laboratory USAUniversity of Wisconsin Madison USA
Department of Physics University of Virginia Virginia USA
~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)~170 PAX Collaborators 34 Institutions (17 inside 17 outside EU)
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
OutlineOutline
WHYWHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
TransversityTransversity
Chiral-odd requires another chiral-odd partnerChiral-odd requires another chiral-odd partner
2Q
- Probes relativistic nature of quarks- No gluon analog for spin-12 nucleon- Different evolution than - Sensitive to valence quark polarization
PropertiesProperties
q
Impossible in DIS Direct Measurement
ppl+l-X epersquohX
Indirect MeasurementConvolution with
unknown fragment fct
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Other Physics TopicsOther Physics Topics
bull Single-Spin Asymmetriesbull Electromagnetic Form Factorsbull Hard Scattering Effectsbull Soft Scattering
ndash Low-t Physicsndash Total Cross Sectionndash pbar-p interaction
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Proton Electromagnetic Formfactors Proton Electromagnetic Formfactors
bullMeasurement of relative phases of magnetic and electric FF in the time-like region
ndash Possible only via SSA in the annihilation pp rarr e+e-
bullDouble-spin asymmetryndash independent GE-Gm separationndash test of Rosenbluth separation
in the time-like region
2
p2
2E
22M
2M
E
y
m4q
|G|)(sin|G|)(cos1
)GGIm()2sin(A
τ
ττ
S Brodsky et al Phys Rev D69 (2004)
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
pp
pp
p (GeVc)
Study onset of Perturbative QCDStudy onset of Perturbative QCD
Pure Meson Landbull Meson exchangebull ∆ excitation bull NN potential models
Transition RegionbullUncharted TerritorybullHuge Spin-Effects in pp elastic scattering
bulllarge t non- and perturbative QCD
High Energybull small t Reggeon Exchangebull large t perturbative QCD
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
pp elastic scattering from ZGSpp elastic scattering from ZGS
Spin-dependence at large-PSpin-dependence at large-P (90deg90degcmcm))
Hard scattering takes Hard scattering takes place only with spins place only with spins
DG Crabb et al PRL 41 1257 (1978)
T=1085 GeV
Similar studies in pp elastic scattering at
PAX
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
OutlineOutline
WHY WHY Physics CasePhysics Case
HOWHOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementsTransversity Measurements
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
P beam polarizationQ target polarizationk || beam direction
σtot = σ0 + σmiddotPmiddotQ + σ||middot(Pmiddotk)(Qmiddotk)
polbeam
polbeam
tt
0
tt
0
ee2
I)t(I
ee2
I)t(I
τ
τ
τ
τ
transverse case
Q0tot
longitudinal case
Q)( ||0tot
For initially equally populated spin states (m=+frac12) and (m=-frac12)
revtpolpol
revtc0beam
fdQ
1
fd)(
1
τ
τ
τ
τ
τ
pol
t
0
pol
tcosheIII)t(I
ttanh
II
II)t(P
beam
Time dependence of P and I
Spin Filter MethodSpin Filter Method
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
statistical error of a double polarization observable (ATT)
NQP
1TTA
Measuring time t to
achieve a certain error
δATT ~ FOM = P2middotI
Polarization Buildup Optimum Interaction TimePolarization Buildup Optimum Interaction Time
(N ~ I)
Optimimum time forPolarization Buildup
given by maximum of FOM(t)
tfilter = 2middotτbeam
0 2 4 6 tτbeam
II 0
02
04
06
08
Beam
Pola
riza
tion
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Experimental SetupExperimental SetupResultsResults
F Rathmann et al PRL 71 1379 (1993)
T=23 MeV
Low energy pp scattering
1lt0 tot+lttot-
Expectation
Target Beam
Experimental Results from Filter TestExperimental Results from Filter Test
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
1992 Filter Test at HD-TSR with protons1992 Filter Test at HD-TSR with protons
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Puzzle from FILTEX TestPuzzle from FILTEX TestObserved polarization build-up dPdt = plusmn (124 plusmn 006) x 10-2 h-1
Expected build-up P(t)=tanh(tτpol)
1τpol=σ1Qdtf=24x10-2 h-1
about factor 2 larger
σ1 = 122 mb (pp phase shifts)Q = 083 plusmn 003dt = (56 plusmn 03) x 1013cm-2
f = 1177 MHz
Three distinct effects
1 Selective removal through scattering beyond Ψacc=44 mrad σR=83 mb
2 Small angle scattering of target protons into ring acceptance σS=52 mb
33 Spin transfer from polarized electrons of the target atoms to Spin transfer from polarized electrons of the target atoms to the stored protonsthe stored protons
σEM=70 mb (-)Horowitz amp Meyer PRL 72 3981 (1994)
HO Meyer PRE 50 1485 (1994)
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Spin Transfer from Electrons to ProtonsSpin Transfer from Electrons to Protons
epep
020
p2
ep2
EM
pa2ln2sin
2C
mp
m14
2
1
Horowitz amp Meyer PRL 72 3981 (1994)HO Meyer PRE 50 1485 (1994)
α fine structure constantλp=(g-2)2=1793 anomalous magnetic momentme mp rest massesp cm momentuma0 Bohr radiusC0
2=2πη[exp(2πη)-1] Coulomb wave functionη=zαν Coulomb parameter (negative for antiprotons)v relative lab velocity between p and ez beam charge number
EM||EM 2
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Dedicated Antiproton Polarizer (AP)Dedicated Antiproton Polarizer (AP)
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
||EM||EM Q2
Siberian Snake
B
Injection
Extraction
150 m
440 m
Polarization Buildup in AP parallel to measurement in HESR
β=02 mq=15middot1017 s-1
T=100 KLongitudinal Q (300 mT)
db=ψaccmiddotβmiddot2dt=dt(ψacc)
lb=40 cm (=2middotβ)
df=1 cm lf=15 cm
F Rathmann et al PRL 94 014801 (2005)
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Beam lifetimes in the APBeam lifetimes in the AP
10 100 1000 T (MeV)
40
30
25
ψacc(mrad)
20102
4
6
8
beam
lilf
eti
me τ
beam (
h)
10
Beam Lifetime
Coulomb Loss
Total Hadronic )T()T(
m4
)T(s1
)m4)T(s()T(s
m4)m2)T(s(4d
d
d)T(
pptot0
2p
2acc
22p
2
2p
22p2
RuthaccC
max
min
)T(f)(d))T()T((
1)T(
revacct0accCaccbeam
τ
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Optimum Beam Energies for Buildup in APOptimum Beam Energies for Buildup in AP
ψacc= 50 mrad
40 mrad
30 mrad
20 mrad
AP Space charge limit
1 10 T (MeV)100 10 mrad
FOM
5
10
15
Maximum FOM
Ψacc
(mrad)
Τbeam
(h)
P(2middotτbeam
)
T(MeV)
10 12 019 163
20 22 029 88
30 46 035 61
40 92 039 47
50 167 042 38
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Space-Charge Limitation in the APSpace-Charge Limitation in the AP
10 mrad1 10 T (MeV)100
ψacc= 50 mrad40 mrad30 mrad20 mrad10 mrad
109
1010
1011
1012
1013
Nind
Nreal
Before filtering startsNreal = 107 s-1 middot 2τbeam
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Transfer from AP to HESR and AccumulationTransfer from AP to HESR and Accumulation
e-coolere-coolerAP
HESR
ABS
Polarizer Target
InternalExperiment
Siberian Snake
B
Injection
Extraction
150 m
440 m
COSY
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
50 mrad40 mrad
30 mrad20 mrad10 mrad
20 40 60 t (h)80
4middot1010
6middot1010
8middot1010
2middot1010
0
Accumulation of Polarized Beam in HESRAccumulation of Polarized Beam in HESRPIT dt=72middot1014 atomscm2
τHESR=115 h
10
HESR2
7
p
1065
e
sp10N
τ
Number accumulated in equilibrium independent of
acceptance
Np
bar
No Depolarization in HESR during energy change
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
How about a Pure Polarized Electron TargetHow about a Pure Polarized Electron Target
1 10 100 T (MeV)
σEM
|| (
mb
)100
200
300
400
500
600
EM||EM 2
Pure Electrons
Atomic Electrons
Maxiumum σEM|| for electrons at rest (675 mb Topt = 62 MeV)Gainfactor ~15 over atomic e- in a PIT
Density of an Electron-Cooler fed by 1 mA DC polarized electrons
bullIe=62middot1015 esbullA=1 cm2
bulll=5 mdt = Iemiddotlmiddot(βmiddotcmiddotA)-1 = 52middot108 cm-2
Electron target density by factor ~106 smaller no match for a PIT (gt1014 cm-2)
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Performance of Polarized Internal TargetsPerformance of Polarized Internal Targets
PT = 0795 0033
HERMES
H Transverse Field (B=297 mT)
HERMES
Dz
Dzz
PT = 0845 plusmn 0028
Longitudinal Field (B=335 mT)
HERMES Stored Positrons PINTEX Stored Protons
H
Fast reorientation in a weak field (xyz)
Targets work very reliably (many months of stable operation)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHEREWHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
NEW Facility
bull An ldquoInternational Accelerator Facility for Beams of Ions and Antiprotonsrdquo
bullTop priority of German hadron and nuclear physics community (KHuK-report of 92002) and NuPECC
bullFavourable evaluation by highest German science
committee (ldquoWissenschaftsratrdquo in 2002)
bullFunding decision from German government in
22003 ndash staging and at least 25 foreign funding
bullto be build at GSI Darmstadt
should be finished in gt 2011 (depending on start)
FAIR(Facility for Antiproton and Ion Research)
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
FAIR ndash Prospects and ChallengesFAIR ndash Prospects and Challenges
bull FAIR is a facility which will serve a large part of the nuclear physics community (and beyond)
- Nuclear structure Radioactive beams- Dense Matter Relativistic ion beams- Hadronic Matter Antiprotons (polarized)
- Atomic physics- Plasma physics
bull FAIR will need a significant fraction of the available man-power and money in the years to come
1 Geuro 10 000 man-years = 100 ldquomanrdquo for 100 years
or (1000 x 10)
bull FAIR will have a long lead-time (construction no physics) staging (3 phases)
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Facilty for Antiproton and Ion Research (GSI Darmstadt Germany)
-Proton linac (injector)-2 synchrotons (30 GeV p)-A number of storage rings Parallel beams operation
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
FLAIR(Facility for very Low energy
Anti-protons and fully stripped Ions)
SIS100300
HESR High Energy Storage RingPANDA (and PAX)
NESR
CR-Complex
The FAIR project at GSIThe FAIR project at GSI
50 MeV Proton Linac
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
HESR
Antiproton Production
Target
HESR (High Energy Storage Ring)bull Length 442 mbull Bρ = 50 Tmbull N = 5 x 1010 antiprotons
High luminosity modebull Luminosity = 2 x 1032 cm-2s-1
bull Δpp ~ 10-4 (stochastic-cooling)
High resolution modebull Δpp ~ 10-5 (8 MV HE e-cooling)bull Luminosity = 1031 cm-2s-1
The Antiproton FacilityThe Antiproton Facility
bullAntiproton production similar to CERN
bullProduction rate 107sec at 30 GeVbullT = 15 - 15 GeVc (22 GeV)
Gas Target and Pellet Target cooling power determines thickness
SuperFRS
NESR
CR
Beam Cooling e- andor stochastic2MV prototype e-cooling at COSY
SIS100300
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
SIS100300
Internal PAX in HESRPolarized antiprotons +
PIT
LoIlsquos for Spin Physics at FAIRLoIlsquos for Spin Physics at FAIR
External ASSIAExtracted beam on PET
(Compass-like)
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
HESR
AP+COSY
The New Polarization FacilityThe New Polarization Facility
Conceptual Design Report for FAIR did not include Spin Physics Jan rsquo04 2 Letters of Intent for Spin Physics
bull ASSIA (R Bertini)bull PAX (P Lenisa FR)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity Measurement at PAXTransversity Measurement at PAX
WHEN WHEN Time ScheduleTime Schedule
ConclusionConclusion
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Transversity in Drell-Yan processes at PAX
p pQL
Q
l+
l-Q2=M2
QT
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
)Mx(q)Mx(qe
)Mx(h)Mx(he
add
ddA
22
q
21
2q
22
q1
q
21
q1
2q
TTTT
dduuq
M invariant Massof lepton pair
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Estimated Luminosity for Double PolarizationEstimated Luminosity for Double Polarization
Polarized Internal Target in HESR
L= dt x frev x Npbar
dt = areal densityfrev = revolution frequencyNpbar = number of pbar stored in HESR
(factor gt70 in measuring time for ATT with respect to beam extracted on solid target)
tot2
7
123110514
1
e
sp10
scm1072106510861027L
Qtarget = 085Pbeam = 03σtot(15 GeV) = 50 mb
In equilibrium
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Signal EstimateSignal Estimate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
d
1) Count rate estimate
)Mx(u)Mx(u
)Mx(h)Mx(ha
dd
ddA
22
21
22
u1
21
u1
TTTT
2) Angular distribution of the asymmetry
Polarized Antiproton BeamPolarized Antiproton Beam rarr rarr Polarized Proton TargetPolarized Proton Target (both transversely polarized)
p pQL
Q
l+
l-Q2=M2
QT
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
AATTTT asymmetry angular distribution asymmetry angular distribution
)Mx(u)Mx(u
)Mx(h)Mx(haA
22
21
22
u1
21
u1
TTTT
Needs a large acceptance detector (LAD)
2cos)cos1(
sin)(a
2
2
TT
bullAsymmetry is largest for angles =90deg
bullAsymmetry varies like cos(2)
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Detector Requirements Detector Requirements
bullDrell-Yan process requires a large acceptance detectorDrell-Yan process requires a large acceptance detector
bullGood hadron rejection needed bull 102 at trigger level 104 after data analysis for single
track
bullMagnetic field Magnetic field bull Increased invariant mass resolution compared to
calorimeterbull Improved PID through Energymomentum ratiobull Separation of wrong charge combinatorial backgroundbull Toroidal Field
Zero field on axis compatible with polarized target
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
One year of data taking at 50 efficiency (180 days) ATTaTT = 03
Expected precision of the h1 measurement
Collider mode 51030 cm-2s-1 Fixed Target 271031 cm-2s-1
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Extension of the ldquosaferdquo regionExtension of the ldquosaferdquo regionDetermination of h1
q(xQ2) not confined to the bdquosafeldquo region (M gt 4 GeV)
Cross section increases by two orders from M=4 to M=3 GeV rarr Drell-Yan continuum enhances sensitivity of PAX to ATT
eeqq
Jqq unknown vector coupling but same Lorentzand spinor structureas other two processes
Unknown quantities cancel in the ratios for ATT but helicity structure remains
Anselmino et alPLB 59497 (2004)
Efremov et al EurPhysJ C35207 (2004)
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
OutlineOutline
WHY WHY Physics CasePhysics Case
HOW HOW Polarized AntiprotonsPolarized Antiprotons
WHERE WHERE FAIR Project at DarmstadtFAIR Project at Darmstadt
WHATWHAT Transversity MeasurementTransversity Measurement
WHENWHEN Time ScheduleTime Schedule
ConclusionConclusion
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Final Remark
Polarization data has often been the graveyard of fashionable theories If theorists had their way they might just ban such measurements altogether out of self-protection JD Bjorken
St Croix 1987
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Measurements at COSYElectron-Proton Spin-Transfer
2005 Verification of σEM at 40 70 and 100 MeV using PIT at ANKE No additional equipment needed
bull weak transverse target guide field (10 G) Qe=Qp
bull Qp pp elastic using Spectator system
bull electron cooling at injection ANKE at 0deg
gt2006 Direct measurement of σEM|| using HERMES-like PIT at TP1
bull strong longitudinal target guide field (3 kG)
ndash needs measurement of Qe
bull Snake in Cooler Telescope (Cooler Sol + WASA Sol)ndash adiabatically switched off after filtering
ndash Qp pp elastic using Spectator system
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
bull Background higher for than for e
Background for Background for Xeepp Preliminary PYTHIA result (2109 events)
bull Background from charge conjugated mesons negligible for e
e
x1000 x100
Total background
x1000 x100
e
Origin of Background
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Andreas Lehrach - Forschungszentrum Juumllich
Methods for Polarization Preservation
bull lt 5 GeV conventional methods correcting dipoles tune jump quadrupoles Siberian snake (solenoid)
bull 5 - 20 GeV adiabatic methods partial snake (helical dipole or
solenoid) ac dipole
bull gt 20 GeV Siberian snake concept Siberian snakes (helical dipole)
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Andreas Lehrach - Forschungszentrum Juumllich
Momentum Kinetic energy
Imperfection resonance
Intrinsic resonance
GeVc GeV G yQG
1789 1082 12- 1871 1155 4 1953 1228 -4+ 2364 1605 13- 2443 1678 5 2521 1752 -3+ 2920 2129 14- 2997 2202 6 3073 2275 -2+ 3465 2652 15- 3541 2725 7 3617 2798 -1+ 4005 3175 16- 4080 3248 8
14172 13265 19+ 14550 13642 36- 14624 13715 28 14697 13789 20+
Depolarizing Resonances in the HESR
Resonance strength
10-6 - 10-2Qy = 814
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Andreas Lehrach - Forschungszentrum Juumllich
AP ~1 Tm solenoidCOSY handled already
HESR 4 helical dipoles (25 Tesla)
+ 15 Tm solenoid Other Equipment
several polarimeters1 spin flipper for HESR (AC dipole)
Polarization Preservation at FAIR
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Andreas Lehrach - Forschungszentrum Juumllich
Siberian Snake for HESR
4 helical dipoles (25 Tesla) and a 15 Tm solenoid
Helical snake
Helical + solenoidal snake
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Andreas Lehrach - Forschungszentrum Juumllich
Magnetic Field Orbit and Spin
Helical dipoles
Solenoid
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
APRe-Cooler
Target
Injection Septum
Snake
RF
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
HESR Accelerator Complex with Polarized Antiprotons
Polarimeter
HESR 15-15 GeVc
COSY-Booster
30 MeV Linac
Snake protonsantiprotons
AP
Natural extension 15 GeV + 15 GeV pbarp Collider
(Spin-gymnastics)
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Double Polarization Experiments Double Polarization Experiments Azimuthal Azimuthal SymmetrySymmetry
(8 coil system under study)
bull 800 x 600 mm coils
bull 3 x 50 mm section (1450 Amm2)
bull average integrated field 06 Tm
bull free acceptance gt 80
Superconducting target field coils do not affect azimuthal acceptance
Possible solution Toroid (6 superconducting coils)Possible solution Toroid (6 superconducting coils)
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
BackgroundBackground
mbpp
50
nbDY 1 108-109 rejection factor against background
bull DY pairs can have non-zero transverse momentum (ltpTgt = 05 GeV)
coplanarity cut between DY and beam not applicable
bull Larger Background in Forward Direction (where asymmetry is smaller)
bull Background higher for than for e (meson decay)
hadronic absorber (needed for inhibits other reactions
bullSensitivity to charge avoids background from wrong-charge DY-pairs
Magnetic field envisaged
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Dream Option Collider (15 GeV)Dream Option Collider (15 GeV)
L gt 1030cm-2s-1 to get comparable rates
Mgt4 GeV
Mgt2 GeV
___ 22 GeV
___ Collider (15 GeV+15GeV)
22 GeV15 GeVCollider 15 GeV+15 GeV
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Theoretical predictionTheoretical prediction
015
02
025TT
TT
a
A
T=22 GeV
T=15 GeV
03
0 06xF=x1-x2
0402
Magnitude of Asymmetry
Angular modulation
Forward Part (FWD) lab lt 8deg
Large Acceptance Part (LAD) 8deg lt lab lt 50deg
Beam and Target PolarizationP=Q=1
LAD
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Estimated signalEstimated signalbull 120k event sample
bull 60 days at L=21 1031 cm2 s-2 P = 03 Q = 085
Events under Jy can double the statistics Good momentum resolution
required
LAD
LAD
ATT=(4304)middot10-2
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Participating Institutions Dzhelepov Laboratory of Nuclear Problems JINR Dubna Russia
Dipartimento di Fisica ldquoA Avogadrordquo and INFN Torino Italy Dipartimento di Fisica Teorica and INFN Torino Italy
Universita and INFN Brescia ItalyCzech Technical Universiy Prague Czech Republic
Charles University Prague Czech Republic DAPNIA CEN Saclay France
Institute of Scientific Instruments Academy of Sciences Brno Czech Republic
NSC Kharkov Physical Technical Institute Kharkov UkraineLaboratoi Nazionali Frascati INFN Italy
Universita dellrsquo Insubria Como and INFN Italy University of Trieste and INFN Trieste Italy
ASSIA CollaborationASSIA Collaboration Spokesperson Spokesperson Raimondo BertiniRaimondo Bertini
bertinitoinfnitbertinitoinfnit
92 Collaborators 12 Institutions (10 EU 2 outside EU)92 Collaborators 12 Institutions (10 EU 2 outside EU)
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Andreas Lehrach - Forschungszentrum Juumllich
Depolarizing Resonances in the HESR
bull Imperfection 25 4 5 6 28
Strong 8 16 24
bull Intrinsic50
-4+ -3+ 20+
12- 13- 35-
Strong 0+ 8+ 12+ 16+ 24- 32+ 36-
bull Coupling50
-4+ -3+ 20+
12- 13- 36-
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Background for Background for Xeepp
Average multiplicity 4 charged + 2 neutral particle per event
Combinatorial background from meson decay
Estimate shows for most processes background under control
pp21hh X
eeK 0
ee0
eeK 0
ee
ee
21hh
hellip
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday
Drell-Yan cross section and event rateDrell-Yan cross section and event rate
q
22
21
22
21
2q
212
2
F2
2
MxqMxqMxqMxqe)xx(sM9
4
dxdM
dbullM2 = s x1x2 bullxF=2QLradics = x1-x2
bull Mandatory use of the invariant mass region below the J (2 to 3 GeV)
bull 22 GeV preferable to 15 GeV
bullx1x2 = M2s
15 GeV22 GeV
Mgt2 GeV
Mgt4 GeV
22 GeV
15 GeV
M (GeVc2)
2 k eventsday