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Spin Physics of NN Interactions at COSY Andro Kacharava Universität Erlangen 16 th SPIN Symposium, Trieste, October 10_16, 2004. Outline. Experiments at COSY NN Interaction Selected Results • NN Elastic • Meson Production • YN Interaction New Equipment Conclusion. - PowerPoint PPT Presentation
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Andro Kacharava Spin Physics at COSY 1
Spin Physics of NN Interactions
at COSY
Andro Kacharava Universität Erlangen
16th SPIN Symposium, Trieste, October 10_16, 2004
Spin Physics at COSY 2
Outline
• Experiments at COSY
• NN Interaction
• Selected Results
• NN Elastic
• Meson Production
• YN Interaction
• New Equipment
• Conclusion
Spin Physics at COSY 3
Experiments: COSY Accelerator
COoler SYnchrotron:
Ions: (pol. + unpol.) p and d
Momentum: 300 to 3700 MeV/c
... unique possibilities:
- Spin Manipulation
- Electron Cooling at Injection
- Stochastic Cooling >1.5 GeV/c
Targets:
- Internal: Solid, Cluster,
Polarized Atomic
- External: Solid, Liquid
Spin Physics at COSY 4
Cooler Synchrotron (COSY) & Detector systems
COSY
ANKE
EDDA
Experiments: Current Facilities
TOF
COSY-11
Spin Physics at COSY 5
NN Interaction
• Fundamental for strong interaction.
• Characterization requires precise data for PSA.
• pp system: up to 2.5 GeV well-known (…, PINTEX, EDDA).
• np system: ANKE-COSY will provide high-quality data.
• Current experimental status:
R.Arndt: Gross misconception within the community that
np amplitudes are known to a couple of GeV.
J.Bystricky: Measurements of ANY observables at small
angle are highly desirable to improve PSAs.
Spin Physics at COSY 6
NN Interaction: Observables
N = yS = xL = z
dσ/d = I0 ·[1+AN·(PN+QN)
+ ANN·PN·QN
+ ASS·PS·QS
+ ASL (PL·QS+PS·QL)
+ ALL·PL·QL]
AN and Aik sensitive only
to spins in initial state: easily accessable
Storage rings - unique environment for double-polarized experiments.
Spin Physics at COSY 7
Selected Results: pp elastic at EDDA
Characterization of NN-interaction
•Large kinematical range: 1.0-3.3 GeV/c, 30°-90° [c.m.]
•High precision data- Unpolarized, single, double polarized.- Large impact on pp PSA >500 MeV.
•Further Results:•No Evidence for dibaryons•Polarimetry for the pp system
T=2.1 GeV
F. Bauer et al., PRL 90 (2003)
Spin Physics at COSY 8
Cooler Synchrotron (COSY) & Detector systems
COSY
ANKE
Experiment: EDDA
TOF
COSY-11EDDA
Spin Physics at COSY 9
Selected Results: pp elastic at EDDA
Characterization of NN-interaction
•Large kinematical range: 1.0-3.3 GeV/c, 30°-90° [c.m.]
•High precision data- Unpolarized, single, double polarized.- Large impact on pp PSA >500 MeV.
•Further Results:•No Evidence for dibaryons•Polarimetry for the pp system
T=2.1 GeV
F. Bauer et al., PRL 90 (2003)
Spin Physics at COSY 10
Selected Results: NN Modeling above 1 GeV
> 1 GeV: Modified model
original + optical potential + Reggezied vector meson
Total
Elastic
Modified model
Original model R.Machleidt (workshop in Tbilisi, Sep’04)
< 1 GeV: Original model – OBE + Δ
Spin Physics at COSY 11
Selected Results: NN Modeling above 1 GeV
R. Machleidt & EDDA data (arXiv:nucl-th/0311002,2003)
PSA (VPI)originalmodified
Spin Physics at COSY 12
Selected Results: Status of NN models >1 GeV
• SATURNE and EDDA: Transition region (few GeV). • NN model for transition region:
- σ reproduced, Spin observables > 1 GeV wrong!- Between 1 and 10 GeV serious problems!
R.Machleidt: Defeat of Theory, Triumph of Experiment.We need new ideas !
Spin Physics at COSY 13
Selected Results: np elastic at ANKE
• Spin structure of np→pn reaction amplitudes
• Method: Spin filter
• Next Step: Measurement of spin observables for pn system up to 3 GeV
• Method: Spectator technique
→ →pd→psp (pn)
dp→(pp)1S0 n
→→
Spin Physics at COSY 14
Cooler Synchrotron (COSY) & Detector systems
COSY
EDDA
Experiment: ANKE
TOF
COSY-11
ANKE
Spin Physics at COSY 15
Selected Results: np elastic at ANKE
• Spin structure of np→pn reaction amplitudes
• Method: Spin filter
• Next Step: Measurement of spin observables for pn system up to 3 GeV
• Method: Spectator technique
→ →pd→psp (pn)
dp→(pp)1S0 n
→→
Spin Physics at COSY 16
NN Interaction: np Amplitudes
In collinearkinematics
over a range in t
;2/,31 2
3
4
qkSIkdtd
d qkS 2,
;
qkSR
2,
2[ ] ;21 22222
20 RIT ;23 2222
22 RIT
R.IC zz *, 2 IC xx *, ;2 RIC yy *, ;2
2222
2220 ,,,, TTdtd
,2;222
20
22 ITI
cos3;2 *,
*, yxzyy ICIC
dp→(pp)1S0 n
→
,RδεβΙ 2222 2
Spin Physics at COSY 17
Selected Results: Test measurement of CE
Spin ModeTheoretical maximum
Intensity[I]Pz Pzz
0 0 0 1
1 -2/3 0 1
2 +1/3 +1 1
3 -1/3 -1 1
4 +1/2 -1/2 2/3
5 -1 +1 2/3
6 +1 +1 2/3
7 -1 -1/2 2/3
COSY Deuteron Beam I = 3 109 fr Acceptance
Spin Physics at COSY 18
Selected Results: dp Reactions
• dp elastic• dp→3He0
• dp→pspd0
• Polarimetry, Luminosity
dp→(pp)n
Spin Physics at COSY 19
Selected Results: Spin dependent amplitudes
)(79.10
0
)(15.086.10
0
SAID
ANKE
22
22
20002
002
T
APTDSG 142(0)
DTAPTDSG 2142 (0)
DSG, DT, APT from SAID
27.0
Value from SAID WI00Error from R. Arndt SE-Solution
T20 = 0.39 ± 0.04 (ANKE)
dp→(pp)1S0 n
→
Method W
orks !
!!
Method W
orks !
!!Bugg, Wilkin, NP A467(1987) 575
Spin Physics at COSY 20
Selected Results: NN program at ANKE
Future polarized ANKE Experiments:
1. Charge-Exchange breakup
2. np Elastic scattering
3. Deuteron breakup
dp→(pp)1S0 n
→ →
pd→psp(pn)→ →
pd →(pp)1S0 n
→ →
Strategy: Begin commissioning of PIT using high rate reactions that can be easily identified (e.g. CE).
Talk S. Yaschenko
Spin Physics at COSY 21
Selected Results: Meson Production
•η production at COSY-11
pp→ppη near threshold
Single Polarization: Ay
distinguish different models...... dominant ρ exchange___ π and η exchange
Double Polarization: Cxx (Cyy)
model independent extractionof amplitudes:
→
P. Winter et al., PLB, 544 (2002)
dashed: 1S0s final state
dash-dotted: 1S0s + 3P0
s
dotted: 1S0s +
3P0s+3P2
s
K. Nakayama et al., PRC, 68 (2003)
Spin Physics at COSY 22
Cooler Synchrotron (COSY) & Detector systems
COSY
ANKE
EDDA
Experiments: Current Facilities
TOF
COSY-11
Spin Physics at COSY 23
Selected Results: Meson Production
•η production at COSY-11
pp→ppη near threshold
Single Polarization: Ay
distinguish different models...... dominant ρ exchange___ π and η exchange
Double Polarization: Cxx (Cyy)
model independent extractionof amplitudes:
→
P. Winter et al., PLB, 544 (2002)
dashed: 1S0s final state
dash-dotted: 1S0s + 3P0
s
dotted: 1S0s +
3P0s+3P2
s
K. Nakayama et al., PRC, 68 (2003)
Spin Physics at COSY 24
Selected Results: YN Interaction
• Strangeness production at COSY-11
• Comparison of Λ - and Σ0 – production via pp p K+Λ/Σ0 close to threshold
• Parameterisation includes:• Individual Λ and Σ0 excitation
functions• p-Y final state interactions
• Hyperon production in pp pK+:• Production mechanism• Next: Double polarization
spin-dependence of p (ANKE, TOF)
Spin Physics at COSY 25
New Equipment : WASA@COSY
• Symmetry and –breaking (ISB, …)
• Hadronic states spectroscopy (, …)
• Baryon-baryon interaction (np, YN)
• Hadronic medium effects (Kaon mass)
Spin Physics at COSY 26
New Equipment: PIT & Spectator Telescope
PIT: Polarized Internal Target::- ABS
- Lamb-Shift Polarimeter
- Storage Cell
Spectator: Silicon telescope array
Talk K. Grigoriev, Sec 8, Oct’15
beam
Spin Physics at COSY 27
New Equipment: Polarized Target for TOF
PT @ COSY-TOF
(H. Dutz et al.,)
PS185/3 @ LEAR set-up Target material test by
Bochum PT-group Components installation
Bonn PT-lab Test of complete system in
spring 2005 Installation at TOF
Status and Outlook
Spin Physics at COSY 28
Cooler Synchrotron (COSY) & Detector systems
COSY
ANKE
EDDA
Experiments: Current Facilities
COSY-11
TOF
Spin Physics at COSY 29
New Equipment: Polarized Target for TOF
PT @ COSY-TOF
(H. Dutz et al.,)
PS185/3 @ LEAR set-up Target material test by
Bochum PT-group Components installation
Bonn PT-lab Test of complete system in
spring 2005 Installation at TOF
Status and Outlook
Spin Physics at COSY 30
Future Experiments: Parity of θ+ (1540)
COSY is perfectly suited to determine the parity free of any model!
Spin-correlation coefficient Axx in pp θ++
+1
-1
50 Q [MeV]0
neg. Parity
pos. ParityA
xx
PLB,590
,(2004),
39-44
Talk Y. Uzikov, Sec 4, Oct’14
Spin Physics at COSY 31
Existing Facilities ANKE, EDDA, COSY11 and TOF
pursue a strong spin physics program
Conclusion
Single and Double Polarization Experiments•NN Interaction (pn)•YN Interaction•pd Dynamics•Meson Production in pp and pn Collisions•Parity of Θ+ Pentaquark
Spin Physics at COSY 32
Observables: np SAID data
APT (KLL) 600 MeV
APT (KLL) 800 MeV
APT (KLL) 900 MeV
DT (KNN) 600 MeV
DT (KNN) 800 MeV
DT (KNN) 800 MeV
DSG 900 MeV
DSG 800 MeV
DSG 600 MeV
Spin Physics at COSY 33
np SAID data: Error analysis
Spin Physics at COSY 34
New Equipment: Spectator Detector
Features:– Three layers (double sided)
1st: 60 m2nd: 300 m3rd: 5 mm
– Ekin~2 MeV (60 MeV/c)
– 800 Channels– Self-triggering– On-board electronics
– UHV compatible– Large Acceptance
• 10% per telescope• 30 mm from the beam
Spin Physics at COSY 35
New Equipment: Polarized Internal Target
• Development for ANKE Atomic BeamSource
Lamb-Shift Polarimeter
Atomic Beam Intensity
7.4·1016 atoms/s (2 HFS)
Lyman- Spectrum
Talk K. Grigoriev, Sec 8, Oct’15
Spin Physics at COSY 36
Luminosity of ANKE PIT
ANKE Luminosity (double polarized)Target density: (2.5 – 7.1)·1013 cm-2
Beam intensity: 5·109 particlesLuminosity: (2.0 - 5.7)·1029 cm-2s-1
L
dbeam
I
ddt t ~ I~ ILL22dd-3-3TT--
½½
Storage cell target requires a small -function at the interaction point: beam~β½
I=7.51016 H/s
T=300 KL=350 mma=15 mmb=20 mm
dt =2.5·1013 cm-2
a=10 mmb=12 mmdt =7.1·1013 cm-2