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Physics with Strange Physics with Strange Hadrons Hadrons
at the at the
SStorage Ring for torage Ring for AAnti-nti-PProtonsrotons
• Physics Highlights • Double Hypernuclei• H-Dibaryon• Properties of Baryons
• Experimental Details
Darmstadt, 5.4.2002
1. Physics Highlights1. Physics HighlightsG
LU
ON
NU
MB
ER
BM
QUARK NUMBER1 3 4 520 6 7
10
2345
HYBRIDSGLUE
BALLS
DI-BARYONS
General IdeaGeneral Idea
s
ud
s
dd
s
ds
s
ss
_
(Kaidalov & Volkovitsky)
quark-gluon string model
_
0
Use pp Interaction to produce a hyperon “beam” (t~10-10 s) which is tagged by the anithyperon or its decay products
_
- capture:
- p + 28 MeV
Production of Double HypernucleiProduction of Double Hypernuclei
-
3 GeV/c
Kaons_
trigger
p_
2. Capture of in
secondary target nucleus
2. Capture of in
secondary target nucleus
1.Hyperon-
antihyperonproductionat threshold
1.Hyperon-
antihyperonproductionat threshold
+23MeV
up to 500
-events per day !
3. -spectroskopy
with Ge-detectors
3. -spectroskopy
with Ge-detectors
- - capturecapture
-atoms: x-rays
conversion
• -(dss) p(uud) (uds) (uds)
• Q = 28 MeV
Conversion probability approximatly 5-10%
Hypernuclei and DeconfinementHypernuclei and Deconfinement
Quark Configuration
Quark Configuration
u d s
Baryon Configuration
Baryon Configuration
p n
s 21
p 23
s 21
p 23
5He5He
4He4He
W
su dusd dd
Tamura et al.
Single HypernucleiSingle Hypernuclei
YN interaction in nuclear mediumNuclear structurenon-mesonic weak decays
p pnn nn
weak baryon-baryon Interaction
Neutronenzahl
16Λ O 18
Λ O14Λ N 15
Λ N12Λ C 13
Λ C 14Λ C
9ΛB 10
Λ B 11Λ B 12
Λ B7ΛBe 8
ΛBe 9ΛBe10
Λ Be6ΛLi 7
ΛLi 8ΛLi 9
ΛLi4ΛHe 5
ΛHe6ΛHe 7
ΛHe 8ΛHe
4ΛH3
ΛH
1 2 3 4 5 6 7 8 9
4
8
7
6
3
5
2
1
10
9
Pro
ton
enza
hl
high resolution -spectroskopy
with germanium detectors
Double HypernucleiDouble Hypernuclei
Multi-Hypernuclei are terra incognita, but they exist !
1963: Danysz et al. 10Be
1966: Prowse 6He
1991: KEK-E176 13B
1991: KEK-E176 3 non-mesonic decays
2001: AGS-E906 4H (~15)
2001: KEK-E373 6He
1
6
10
13
Hyperkern ( ) ( ) ( ) ( )
4.1 3.1
11.0 6.7
16.2 11.4
A AB Z MeV B Z MeV
He
Be
B
NAGARA
6- 12 4
6 5
ΛΛ
-ΛΛ Λ
Ξ + C + He+t
He He+ π
He
p+
Kerne as FemtolaboratoryKerne as Femtolaboratory
H-Particle R.L. Jaffe (1977)
free coalescencet ~ 10-23s
nuclear breeder
t ~ 10-10s
neutron stars
S=-2 Nuclei and H-dibaryon statesS=-2 Nuclei and H-dibaryon states
H-particle in nucleus free H
(see e.g. T. Yamada, NP A691 (2001) 250c; (3q)+(3q) quark cluster model )
free H-dibaryonH-dibaryon in 10
YYBe
B=12.2 MeV B=24.0 MeV
Contributions to intrinsic quadrupole moment of baryons• One-gluon exchange• Meson exchange
J=1/2 baryons have no spectroskopic quadrupole moment
- Baryon:• J=3/2• long mean lifetime 0.82·10-10 s• only one-gluon contributions to quadrupole moment
(A.J. Buchmann Z. Naturforsch. 52 (1997) 877-940)
Fundamental Properties of BaryonsFundamental Properties of Baryons
3 2 2( )(3 )iQ d r r z r
s
ss
1/ 221/ 2
(3 ( 1)) 0z
Js z J
Q J J J
A very strange AtomA very strange Atom
atoms by produktion
hyperfine splitting in -atom
electric quadrupole moment of
• prediction Q= (0 - 3.1) 10-2 fm2
• E(ℓ=10 ℓ=9) ~ 515 keV
• EQ ~ few keV for Pb
-
spin-orbit Eℓs ~ (Z)4 ℓm
quadrupole EQ ~ (Z)4Qm3
spin-orbit Eℓs ~ (Z)4 ℓm
quadrupole EQ ~ (Z)4Qm3
Q= +0.02 fm2
Q= - 0.02 fm2
high resolution -spectroscopy
Experimental DetailsExperimental Details
-- properties properties
minimal distance production capture
initial momentum 100-500 MeV/c range ~ few g/cm2
- mean lifetime 0.164 ns
DetektorkonzeptDetektorkonzept
hermetic (4)
high rate
PID (, e, , , K, p)
trigger (e, , K, D, )
compact (€)
modular
Elektronenkühler
InjektionKicker Septum
Solid state-micro-tracker• thickness ~ 3 cm
High rate Germanium detector
The Solid State Micro TrackerThe Solid State Micro Tracker
electronic „emulsion“ detector
real time tracking of• incoming -
• decay products (p,)
different absorbers as secondary target
two posibilities• capillar detector (2D)• pixel detector (3D)
NAGARA
6
5
-
Λ
12 4
6 -ΛΛ
ΛΛΞ + C + He+
He
t
He + π
He
p+
Capillary-DetektorCapillary-Detektor
glas capillary filled with liquid scintillator
20m - interaction (CHORUS)
fast readout: hybrid-photomultiplier+ALICE pixel chip ?!
only 2D projection
CMOS Monolythic Active Pixel CMOS Monolythic Active Pixel SensorSensor
Technology borrowed from digital still and video cameras
p wellpixel circuit
industrial fabrication process (low cost)
system-on-a-chip (amplifier, ADC...)
good spatial resolution (~1m)
thin (20-50 m seems possible)
example: MIMOSA Chip (IReS/LEPSI)
charge collection by diffusion time
100-150 ns
Prospects for MAPSProspects for MAPS
The good performance of CMOS MAPS in charge particle detection has been successfully demonstrated with small scale prototypes:
~99%, ~1.5-2.5 m, S/N~20-40
Further optimization of the sensitive element design is under way
Large scale prototype sensors (2x2 cm2 - 12x2 cm2) are expected soon (0.6 mm AMS process)
Development of an advanced design of processing electronics with more functionalities at a pixel and chip levels, more data processing ‘on-chip’, data sparsification – a major task
Sensor radiation hardness is expected to be improved via design studies R&D program on CMOS MAPS TESLA VD in a collaboration with several other centers just started – aim for the detector design by 2004.
Yu. GornushkinYu. Gornushkin 7th International Conference on Advanced Technology and Particle Physics, 17 /10/2001 7th International Conference on Advanced Technology and Particle Physics, 17 /10/2001
SetupSetup
beam: 3 GeV/c, 1mm; no halo (roman pots?)
Tracking detector for -
• 2-3 cm thick
• sandwich structure (50m+150m)
• secondary target support, cooling
p--
readout
primary target
secondary target
pixel detector
ConclusioConclusionn
Strange baryons offer a unique and important complement to the presented program at the Storage ring for Anti Protons.
Many interesting technical challenges:• Solid state micro tracker• high rate germanium arrayG
LU
ON
NU
MB
ER
BM
QUARK NUMBER1 3 4 520 6 7
10
2345
HYBRIDSGLUE
BALLS
DI-BARYONS
Das HESR TeamDas HESR Team
T. Barnes, D. Bettoni, R. Calabrese,
W. Cassing, M. Düren, S. Ganzhur,
A. Gillitzer, O. Hartmann, V. Hejny,
P. Kienle, H. Koch, W. Kühn, U. Lynen,
R. Meier, V. Metag, P. Moskal, H. Orth,
S. Paul, K. Peters, J. Pochodzalla,
J. Ritman, M. Sapojnikov, L. Schmitt,
C. Schwarz, K. Seth, N. Vlassov,
W. Weise, U. Wiedner
HHEESSRR
„Quarks, quarks, quarks.“