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Israeli Participation in
Heavy Ions and Fixed Target Experiments
(HE and Nuclear Physics)
Restricted ECFA meeting
Israeli Academy of Science, Jerusalem
Friday, 21 May 2005
E. Piasetzky
School of Physics and Astronomy
Tel Aviv University
• Scientific program and physics highlights.
Hardware Contributions.
People, group size, and activities.
Summary and overview.
Outline:
Period: 1990-2005
More information can be found in slides 37-80 which do not have time to present.
Experimental groups in Israel:
Relativistic heavy Ion:Relativistic heavy Ion:
1990-1999 NA45 / CERES at CERN
1999- NOW PHENIX / RHIC at BNL
Fixed Target particle physics experiments:
Experiments at Fermilab:
E 781 (SELEX)E 665
E 791
measurement of the pion valence – quark momentum distribution.
Search for particles made of 5 and 6 quarks.
Observation of Color-Transparency in Diffractive Dissociation of pions.
Double Charm Baryon Spectroscopy.
Polarization Measurement of the Lambda produced in Deep inelastic muon scattering.
COMPASS at CERN
NA-47 (SMC) at CERN
Determination of the gluon polarization.
Spin structure of the nucleon.
Π Polarisabilities via Primakof reaction.500-50 GeV
Scientific program
GeVSNN 200
GeVSNN 17
EVA at Brookhaven National Lab.
Study of hard proton induced reactions.
Measurement of short range correlation in nuclei.
E850 / EVA
Experiments at Jefferson Lab.
Measurement of the neutron charge FF: GEn
Measurement of short range correlation in nuclei.
Hard photo-disintegration of a pp pair.
E02-013, E93-0026
E01-015 E03-101
Mainz Microtron MAMIA2 collaboration
Measurement of the π+ polarizabilities.
TRIUMF: Measurements of pion integral cross sections for low and the 3,3 resonance energy regions.
PSI : Precision measurement of elastic scattering of low energy π+ , π- on nuclei.
Total π- p SCX cross sections between 40-240 MeV.
1-20 GeV
20-300 MeV
Scientific program
Radioactive nuclear beamsRadioactive nuclear beams
Measurements of ground-state magnetic moments of short-lived Mirror Nuclei.
ISOLDE / CERN
Precision measurement of the 7Be(p,gamma)8B cross section.
Parity non-conservation in 180mHf.( An experiment to be run in 2005).
Study of nuclear astrophysics reactions using ion beams.
SARAF (Soreq Applied Research Accelerator Facility)
TRIUMF Radioactive beam and Neutral Magneto-Optical atom Trap
Symmetry Tests in β Decay.
0-2 MeV
Scientific program
Main CERES Result: strong enhancement of low-mass dileptons hinting at Chiral Symmetry Restoration
Strong enhancement of low-mass e+e- pairs in A-A collisions(w.r.t. to expected yield from known sources)
No enhancement in p-Be and p-AuQuantitative explanation requires:thermal radiation from high-density
with in-medium modification of theintermediate meson hinting at
chiral symmetry restoration
Spectral shape broadening
HG +- * e+e-
dropping meson mass
hadron cocktail
free meson
physics highlights
Main PHENIX Results• discovery of jet quenching (suppression of high pT particles).
• very high energy density state (30-100 times dense than normal nuclear matter).
• rapid equilibration.
• strongly interacting system exhibiting collective behavior.
• suggestion of a perfect primordial fluid (almost zero viscosity), behaving more like a liquid, not as a gas.
d-Au
Au-Au
0 yield w.r.t. to pp collisions
The first PHENIX paper (PRL 86, 3500 (2001)) is based on an analysis of the WI group.
physics highlights
E 791 / FNAL : Direct measurement of the pion valence – quark momentum distribution
... ggqq gqq qqa The pion wave function can be expanded in terms of Fock states:
The valence (first) state with the minimal gluon content, very small size, large mass, is about 25% of the light cone wave function.Diffractive dissociation of 500 GeV/c π - into di-jets from a platinum target at FNAL exp 791 allows to measure the internal momentum distribution of the valence quarks in this state.
Q2~16(GeV/C)2Q2~8 (GeV/C)2
The light-cone asymptotic wave function describes the data well for Q2>10 (GeV/c)2.
physics highlights
SELEX, the charm hadro-production experiment (E781) at Fermilab opened a new horizon for charm baryon spectroscopy.
SELEX 4 double charm states .
physics highlights
First observation of the Doubly Charmed Baryon (3520) cc PRL 89 (2002) 112001
Confirmation via another decay mode:
Analysis done at TAU
Submitted to PRL ( hep-ex / 0406033)
SELEX : Kccc pKc
pKDcc KD
The two decay modes give consistent mass. The averaged mass is 3518±3 MeV/c2.
The relative branching ratio:
)()( KKpD cccccis
0.0450.078
physics highlights
How ΔG/G is measured
Photon-Gluon Fusion (PGF) G
GAPGF
N
ggG
ΔG/G from high pt hadron pair, Q2 > 1
ΔG/G = 0.06 ± 0.31stat. ± 0.06syst.
Open charm
cc
4%) (BR 0 KD
ccDD .0*
At this point only raw asymmetry is available.
Preliminary result based on 2002-2003 data.
q
q
N
physics highlights
Measurement of short range correlations in nuclei.E 01 - 015
The method:
To study nucleon pairs at close proximity and their contribution to the large momentum tail of nucleons in nuclei.
The goal:
“Redefined” the problem in momentum space
A pair with “large” relative momentum between the nucleons and small CM
momentum.
p
e
ep
n
HRSHRS
BigBite
n-array
Experimental setup:
physics highlights
Precision measurement of elastic scattering of 21.5 MeV π+, π- on Si, Ca, Ni, and Zr.
The Goal: Testing the “anomalous” s-wave repulsion as observed in pionic atoms.
Method: using the πE3 channel of PSI and the low energy pion spectrometer (LEPS).
Results:
The extra repulsion observed in pionic atoms data was confirmed by the scattering data.
In medium modified pion decay constant reconcile the π-nucleus and πN interactions.
This is consistent with a recent suggestion by Weise et al. using chiral restoration model.
PRL 93 (2004) 122302.
physics highlights
Hardware Contributions:
•All the gas detectors for CERES were designed,
constructed and operated by the WI group.
Double RICH spectrometer – no real tracking
Readout chambers of the two RICH detectors
CERES Spectrometer: 1992
CERES Spectrometer: 1995
Add tracking with a doublet of SiDC before, and a pad chamber after the double RICH spectrometer Add Pad Chamber
CERES Spectrometer: 1999
Improve tracking and mass resolution with a radial TPC
Readout chambers of the TPC PHENIX
Hardware Contributions
Essential components of the PHENIX particle tracking
system.
Composed of three layers of pixel detectors PC1, PC2
and PC3.
PC1 (design, construction, installation…) is the
responsibility of WI group.
Hardware Contributions:
A sector of PC1 mounted on the drift chamber and ready to be installed on the PHENIX central arm (photo taken in 9/99).
Pad Chambers
Hardware Contributions:
Design construction and operation of HBDHadron Blind Detector for PHENIX
♣ windowless Cherenkov detector (L=50cm)
♣ CF4 as radiator and detector gas
♣ CsI reflective photocathode
♣ Proximity focus: detect blob not ring
♣ Triple GEM with pad readout
HBD concept
Final HBD design
Detectors built by the experimental group at Tel Aviv University are moved to be installed in the experimental Hall A of the Jefferson Lab.
Dec. 2004
The n-array
Scintillator hodoscopes for the BigBite spectrometer
Hardware Contributions:
ISOLDE + Tilted-foil polarization + HV Platform + β NMR
60 KeV BEAM
250 kV
Atomic polarization
Static magnetic field + perturbing rf field
IN THE FUTURE: REX-ISOLDE
Hardware Contributions:
Measurements of ground-state magnetic moments of short-lived Mirror Nuclei
Accelerator Layout
176 MHz RFQ
1.5 MeV/u M/q ≤ 2
1st cryostat 6 SC HWR 176 MHz 0=0.09
2nd – 6th cryostats 40 SC HWR 176
MHz 0=0.15
ECR Ion Source 20 keV/u
Phase I2006
Phase II2009
Accelerator purchasedfrom Accel GmbH,Bergisch-Gladbach,Germany
SARAF (Soreq Applied Research Accelerator Facility)
Soreq Nuclear Research CenterYavne, Israel
Accelerator Basic Characteristics
ParameterParameter ValueValue CommentComment
Ion Species Protons/Deuterons M/q ≤ 2
Energy Range 5 – 40 MeV
Current Range 0.04 – 2 mA Upgradeable to 4 mA
Operation 6000 hours/year
Reliability 90%
Maintenance Hands-On Very low beam loss
A RF Superconducting Linear Accelerator
People, group size, and activities.
Experimental groups in Israel:
Weizmann Institute of Science
Zeev Fraenkel Itzhak Tserruya
• 3 academic staff
• 1-3 post-docs
• 2-4 students
Present total staff: 8 people
• 9 PhD theses: in the period
1993-2006
The Heavy Ion Group:The Heavy Ion Group:
Group leader: Itzhak Tserruya
More information in slides 37 - 46.
Ilia Ravinovich
Gvirol Goldring
Weizmann Institute of Science
Michael Hass
3 scientists
4 post docs
3 students
1-2 technician -years
The WI group started its activity at ISOLDE IN 1990. The group is not a member of the ISOLDE collaboration and carried the experiments on an ad-hoc basis.
More information in slides 47 - 50.
Michael PaulEliahu Friedman
2 scientists
4 students
•5 PhD (7 M. Sc.) theses:
in the period 1990-2006
More information in slide 51.
Jechiel Lichtenstadt
Danny Ashery
Murray Moinester
Eli Piasetzky
Jonas Alster
Avivi Yavin
6 scientists
4 students
1 technician
Present active staff : 9 people
•12 Ph.D (14 M. Sc.) theses
in the period 1990-2006
More information in slides 55 - 80.
Last but not least:
The experimental program was carried in intensive collaboration with the theoreticians here in Israel:
Weizmann Institute:Weizmann Institute:
Shmuel Gurvitz Zvi Lipkin
Avraham Rinat
Igal Talmi
Michael W. Kirson
Hebrew University:Hebrew University:
Barnea Nir
Avraham Gal Ami Leviatan
Victor Mandelzweig
Tel Aviv University:Tel Aviv University:
Naftali Auerbach
Leonid Frankfurt Evgeny Levin
Marek Karliner Shmuel Nussinov
Benjamin Svetitsky
The late: Judah Eisenberg
Summary and overview.
The fixed target and heavy ion program carried by Israeli groups during 1990-2005 was rich and widespread:
Energies: RHI: - GeVSNN 20017
Accelerators laboratories: CERN ,Mainz, PSI,Fermi., Brookhaven, Jefferson, TRIUMF
Physics interest: QGP, hadron structure, strong interaction, symmetry tests, nuclear structure and reaction.
Fixed target: 0-500 GeV.
d-Au
Au-Au
0 yield
Experiment Experimental group
Initiators Major equipment contribution
Major participation in analysis
Special physics topic
Management positions
PHENIX/RHIC W.I.. √ √ √ .. on executive council
CERES /CERN W.I.. √ √ √ .. Spokesperson
SELEX / Fermi T.A.U. minor √ Double charm
E991 / Fermi T.A.U. Penta,CT, LCWF
COMPASS /CERN
T.A.U. √ on executive council
E850 / BNL T.A.U. √ √ √ SRC
GeN / JLab. T.A.U. √ √
S.R.C/ JLab T.A.U. √ √ √ . Spokesperson
MAMI/Mainz T.A.U. √ √ .
Π /TRIUMF H.U. √ √ Spokesperson
MM / ISOLDE W.I.. √ √ √ Spokesperson
MOT/TRIUMF T.A.U. √
Israeli participation
The program has been carried by experimental groups in Weizmann Inst., Hebrew University , and Tel Aviv University.
Faculty - 14 The current total number of people doing research in this field (faculty, postDocs., students, technicians): ~ 30.
30 Ph.D. theses in the period 1990-2005.
Experiment Total collaboration
Number of institutes
Experimental group
Number of people
PHENIX/RHIC 300 44 (7) W.I.. 6
CERES /CERN 40 8 (5) W.I.. 6
SELEX / Fermi 100 20 (5) T.A.U. 4
E991 / Fermi 80 18 (4) T.A.U. 5
COMPASS 230 31 (7-8) T.A.U. 2
E850 / BNL 24 8 (3) T.A.U. 5
GeN / JLab. 110 20 (5) T.A.U. 5
S.R.C/ JLab T.A.U. 3
MAMI/Mainz 30 9 (3) T.A.U. 2
Π /TRIUMF 11 4 (3) H.U, 2
MM / ISOLDE 11 5 (2-3) W.I. 6
MOT/TRIUMF 22 6 (3-4) T.A.U 1
Israeli participation
Funding: I.S.F., B.S.F., G.I.F.
~400,000 €/year
FNAL-SPS-RHIC (HE: E>50GeV): ~75%
Others: ~25%
Heavy Ion Group of the Heavy Ion Group of the Weizmann InstituteWeizmann Institute
1990-1999 NA45 / CERES at CERN
1999- NOW PHENIX / RHIC at BNL
Hardware Contributions
• CERES: all gas detectors designed, constructed and
operated by the WI group:
1990-92: Readout chambers of the two RICH detectors
1995: Pad Chamber
1999: Readout chambers of the TPC
• PHENIX
1999: Design, construction and operation of Pad Chambers
2003-4: R&D of an Hadron Blind Detector for PHENIX
2005-6: Design construction and operation of HBD
CERES Spectrometer: 1992
First use of RICH detector in HI physics First use of Si radial drift chambers in an experiment Double RICH spectrometer – no real tracking Unique features to cope with the high multiplicities:
High gamma threshold tiny fraction of charged hadrons emit Cherenkov light UV detectors upstream of target not traversed by huge flux of forward particles
Field free region in RICH1 for effective recognition of 0 Dalitz and γ conversions
Radiator gasCH4 (γth = 28)
Carbon fiber mirrorCaF2 window
Si drift chambers
TMAE 2 PPAC + MWPCPad readout
CERES Spectrometer: 1995
Add tracking with a doublet of SiDC before, and a pad chamber after the double RICH spectrometer
CERES Spectrometer: 1999
Improve tracking and mass resolution with a radial TPC
Pad Chambers
Essential components of the PHENIX particle tracking
system.
Composed of three layers of pixel detectors PC1, PC2
and PC3.
PC1 (design, construction, installation…) is the
responsibility of WI group.
HBD concept ♣ windowless Cherenkov detector (L=50cm)
♣ CF4 as radiator and detector gas
♣ CsI reflective photocathode
♣ Proximity focus: detect blob not ring
♣ Triple GEM with pad readout
Very attractive features:
Unprecedented N0
Bandwidth 6 - 11.5 eV N0 ≈ 800 cm-1 ~35 pe in a 50 cm radiator
Reflective photocathode no photon feedback Pad size comparable to blob size (~10 cm2) hadrons: single pad hit, electrons: more than one pad hit
Low granularity: ~3000 pads to cover central arm acceptance
Low gain primary charge of at least 10 e/pad gain of 5 103 is enough
Final HBD design • Acceptance ||| ≤0.45 | ≤0.45 =135=135oo
• pad size a = 15.6 mm
• Number of channels 2304
• Number of detector modules 24
• GEM size 23 x 27 cm2
Management Positions
(I. Tserruya)
• 1989-91 Initiators of the CERES experiment together with the Heidelberg University group.
•1993-1998: Spokesman of CERES
• 2001-4: Member of PHENIX Executive Council
• 2004- present: Subsystem manager of the PHENIX HBD
upgrade project
Group activities 60 papers published in the refereed literature
• 21 from CERES• 39 from PHENIX• 26 of them published in PRL or PL a)
• 9 of them are top cite 100+ in SPIRES-HEP• Over 100 papers published in Conference Proceedings.
Major impact of the WI group• in the dielectron analyses of CERES• in at least 9 papers from PHENIX
49 invited talks • delivered by members of the WI Heavy-Ion Group at International Conferences or Workshops during the period 1995-2005• 12 of them on behalf of CERES or PHENIX.
a) First PHENIX paper (PRL 86, 3505 (2001)) based on an analysis of the WI group. Cited 164 times.
The Radioactive nuclear beams The Radioactive nuclear beams Group of the Weizmann InstituteGroup of the Weizmann Institute
Measurements of ground-state magnetic moments of short-lived Mirror Nuclei.
ISOLDE / CERN
Precision measurement of the 7Be(p,gamma)8B cross section.Parity non-conservation in 180mHf.( An experiment to be run in 2005).
Measurements of ground-state magnetic moments of short-lived Mirror Nuclei
23Mg (12 p + 11n )
T1/2=11.3 sec
23Na (11p + 12n)
stable
17Ne (10 p + 7n ) T1/2=109 msec
17Ne (7 p + 10n ) T1/2=4.2 sec
FUTURE: 55Ni -- 55Co, 59Zn -- 59Cu …...
8B is the major source of high-energy solar neutrinos.The discrepancies between measurements of the 8B production cross section before this work were up to 20%, reflecting the systematic problems in these measurements.
The spallation product ,7Be, produced in a PSI graphite production target were directly implanted, using the 60 keV beam at ISOLDE (CERN) on a copper substrate.
The new technique:
The measurements were done using the WI 3 MeV Van De Graaff accelerator. Measurements at a few incident proton energies (with a precision of about 2% ) allow extrapolation to zero energy –as required for the astrophysical studies.
PRL 90 (2003) 022501-1
Precision measurement of the 7Be(p,gamma)8B cross section
Parity non-conservation in 180mHf
A proposal to ISOLDE (to be run in 2005)
8+
8-
6+
0+
MeV
1.14221.0847
0.6411
0
501 KeV
The large forbidden 8- 6+ is very sensitive to even a small parity non-conserving mixing between the two proximate 8+ and 8- states.
The experiment will use the unique 180mHf beam provided by the isotope separator at ISOLDE. The continuous implantation of the 180mHf will build up low temperature nuclear oriented sample of metastable Hf nuclei that will allow measurement of the angular distribution of the gamma emission from the required transition, using Ge detectors.
The experimental nuclear physics group The experimental nuclear physics group at the Hebrew Universityat the Hebrew University
TRIUMF: Measurements of pion integral cross sections for low and the 3,3 resonance energy regions.
PSI : Precision measurement of elastic scattering of low energy π+, π- on nuclei.
Total π- p SCX cross sections between 40-240 MeV.
Phenomenological analysis of data related to pionic atoms, sigma atoms, K+ , K- and antiproton nuclear reactions.
Study of nuclear astrophysics reactions using ion beams.
AMS and other dating methods for archeological, astrophysics, environmental, geophysics, and biomedical research.
Accelerator LayoutSARAF (Soreq Applied Research Accelerator Facility)
Soreq Nuclear Research CenterYavne, Israel
Nuclear Astrophysics.
Radioactive beams.
Phase-I : Nuclear Astrophysics
1.91 MeV
proton beam
vacuum
Li jet
Graphite dump and moderator
Cu backing heat removal
target
Li jet
Neutron flux estimate :
n(Li) ~ 120 mb (Ep= 1.89 – 1.91 MeV)x(Li) ~ 0.150 mg/cm2
n/p = 1.6 x 10-6
Ip = 5 mA dn/dt = 0.5 x 1011 n/s2 x 1011 n cm-2 s-1
double-neutron capture - 135Cs yield:135Cs/133Cs ~ 10-14 /week
(Proposed by M. Paul, Hebrew University at Jerusalem)
Radioactive beams
0
20
40
60
80
100
120
0 2 4 6 8 10
Energy (MeV)
Cro
ss
se
cti
on
(m
b)
Bass 1961Savilev 1958Stelson 1957Stelson 1957
9Be(n,)6He
RIB T1/2
(ms)
reaction SARAF calculated production rate (atoms/sec)
(Before post-Acceleration)
Post accelerator count rate
(atoms/sec)
6He 807 7Li(p,2p) 1011 Dubna 1.5x105 @ 25 MeV/u
Ganil 9x107 @ 7 MeV/u
6He 807 9Be(n,) 1013
8Li 838 11B(n,) 1013 TRIUMF 8x108 @ 1.5 MeV/u
8B 770 12C(p,2p3n) 1011 Texas A&M 104 @ 8 MeV/u
Production rate at 2 mA and 40 MeV
d beam
Hot Be target Cold Be
target
9Be(d,xn)
9Be(n,)6He
fast n
2-step production
(Proposed by M. Hass, Weizmann Institute of Science)
Fixed Target Experiments at Fermilab:
E 781 (SELEX)E 665
E 791
The experimental nuclear The experimental nuclear physics group at Tel Aviv physics group at Tel Aviv UniversityUniversity
measurement of the pion valence – quark momentum distribution.
Search for particles made of 5 and 6 quarks.
Observation of Color-Transparency in Diffractive Dissociation of pions.
Double Charm Baryon Spectroscopy.
Polarization Measurement of the Lambda produced in Deep inelastic muon scattering.
COMPASS at CERN
EVA at Brookhaven National Lab.
Study of hard proton induced reactions.
Measurement of short range correlations in nuclei.E850
NA-47 (SMC) at CERN
Determination of the gluon polarization.
Spin structure of the nucleon.
Π Polarisabilities via Primakof reaction.
The experimental nuclear The experimental nuclear physics Group at Tel physics Group at Tel Aviv UniversityAviv University
Mainz Microtron MAMI
A2 collaboration
TRIUMF Radioactive beam and Neutral Magneto-Optical atom Trap
Symmetry Tests in β Decay.
Experiments at Jefferson Lab.
Measurement of the neutron charge FF: GEn
Measurement of Short range correlation in nuclei.
Hard photo-disintegration of a pp pair.
E02-013, E93-0026
E01-015 E03-101
Measurement of the π+ polarizabilities.
E 791 / FNAL : Observation of Color-Transparency in Diffractive Dissociation of pions
If there is a fully coherent interaction between the pion and all the nucleons in the nuclei and the Di-jets do not have final state interaction in the nucleus then:
)(A )( NMAM 0q A 2t
22
tdq
d 34
A
Measured :
0.1 1.5 PRL 86,4773 (2001)
In agreement with calculations: PL B304 (1993).
Danny Ashery Murray Moinester
3 scientists
E791:
4 students
E791:
2 students
1 postdoc
The COMPASS spectrometerThe COMPASS spectrometer
Spin physics program:
Gluon polarization
Transversity.
Hadron program:
Polarisabilities of pions via the Primakoff reaction.
From asymmetry measurements of lepto-produced: High pt hadron pairs.
Open charm.
How to measure ΔG/G
Photon-Gluon Fusion (PGF)
G
GAPGF
N
ggG
Two tagging methods:High pt hadron pairsOpen charm
ΔG/G from high pt hadron pair, Q2 > 1
ΔG/G = 0.06 ± 0.31stat. ± 0.06syst.
Open charm
cc
4%) (BR 0 KD
ccDD .0*
At this point only raw asymmetry is available.
Preliminary result based on 2002-2003 data.
q
q
N
Primakoff trigger
Π Polarisabilities via Primakof reaction
Hadron pilot run 2004:
30’000 – 40’000 Primakoff events on Pb after cuts.
More than four times statistics of previous experiment. Analysis in progress.
Jechiel Lichtenstadt Murray Moinester
2 scientists
Measurement of the π+ polarizabilities via
n p
Mainz Microtron MAMI electron accelerator. A2 collaboration.
1500 beam hours.
MeV 817-537 E 00' 180 - 140 cm
This experiment:
elsyststat mod5.00.35.16.11()(
Murray Moinester
1 scientist
1 student
38Ar
e+
Symmetry Tests in β Decay using the TRIUMF Radioactive beam and Neutral Magneto-Optical atom Trap (MOT).
38mK
Symmetry Tests in β Decay using the TRIUMF Radioactive beam and Neutral Magneto-Optical atom Trap (MOT).
In the standard model a 38mK(0+)38Ar(0+) β decay with back to back β-neutrino emission is forbidden (cannot be produced from a W-exchange). The atoms suspended in space decay in the MOT and the angular correlation between the recoil nuclei and the β was used to set a limit on the existence of scalar boson contribution.
See nucl-ex/0412032, PRL 94 142501 (2005).
Best direct limits on massive (a few MeV) neutrino admixtures to electron neutrino. See PRL 90 (2003) 012501.
Parity and time reversal violation tests are planned using polarized 37K decay.
Danny Ashery
1 student
To study nucleon pairs at close proximity and their contribution to the large momentum tail
of nucleons in nuclei.<1 fm
K 1 > KF ,
K 2 > KF
K 1
K 2
K 1 K 2
“Redefined” the problem in momentum space
A pair with “large” relative momentum between the nucleons and small CM
momentum.
NN SRC
We know that there are nucleons in nuclei with large momentum .
35%-25 K k : F12 CFor
We know that 2NN SRC are responsible for some of the large momentum components in the nucleus.
The purpose of this measurement is to find the fraction of 2N SRC in the tail of the
nucleon momentum distribution.
NN stands for pp or np pairs
KF
p
e
e’*
n
p
e
e’*
p
The method:
We measure the fraction of (e,e’p) events in which NN correlated nucleons are observed, as a function of the missing
momentum of the proton in the nucleus.
)e,e’p ( spectral function ) P ,( m
mES
)e,e’pN ( decay function
) , ,( smm PPED
),S(E d ),,( m3
mssmm PpPPED
p
e
e’
*n
p
Pm
= 3
00-6
00 M
eV/c
99 ±50
P =
300
-600
MeV
/c
Ee = 5 GeV
Ee’ = 4.15 GeV
Q2=2 (GeV/c)2
qv=1.65 GeV/c
50.40
17.80
40.80
p = 1.45 GeV/c
The selected kinematics for the measurement
X=1.245
Experimental setup
HRSHRS
p
e
e
p
Big Bite
n array
EXP 01-015
n
Scattering chamber
Milestones Jan 1998
Proposal 97-106
Hall C , n - array as a 3rd arm
Approved by PAC 13 with priority B +
Jan 2000
Parasitic 3He(e,epn) measurement in Hall A with E89 - 44
Jan 2001
P 01 -015 (update of 97-106)
Hall A, BigBite and n-array
Approved by PAC 19 with priority B+
Milestones
April 2001
Triple coincidence test d(e,epn)
Nov 2002
Measurement of low momentum, large angle positive charge singles at Hall A
Nov 2001
Parasitic measurements and shield studies
of n – detectors at Hall A
July 2003
Readiness reviewJan – April 2005
beam time
Dec 2004
Commission
Jechiel Lichtenstadt
Eli Piasetzky
2 scientists
1 student
3 technician -years