Spin Physics of NN Interactions

1

• Spin Physics of NN Interactions
• at COSY
• Andro Kacharava
• Universität Erlangen
• 16th SPIN Symposium, Trieste, October 10_16, 2004

2
Outline

• Experiments at COSY
• NN Interaction
• Selected Results
• NN Elastic
• Meson Production
• YN Interaction
• New Equipment
• Conclusion

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 gt1.5 GeV/c
Targets - Internal Solid, Cluster,
Polarized Atomic - External Solid,
Liquid
4
Experiments Current Facilities
Cooler Synchrotron (COSY) Detector systems
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.

6
NN Interaction Observables
Storage rings - unique environment for
double-polarized experiments.
ds/d? I0 1AN(PNQN)
ANNPNQN ASSPSQS
ASL (PLQSPSQL)
ALLPLQL
AN and Aik sensitive only to spins in initial
state ? easily accessable
N y S x L z
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 gt500 MeV.
• Further Results
• No Evidence for dibaryons
• Polarimetry for the pp system

T2.1 GeV
F. Bauer et al., PRL 90 (2003)
8
Experiment EDDA
Cooler Synchrotron (COSY) Detector systems
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 gt500 MeV.
• Further Results
• No Evidence for dibaryons
• Polarimetry for the pp system

T2.1 GeV
F. Bauer et al., PRL 90 (2003)
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Selected Results NN Modeling above 1 GeV
R.Machleidt (workshop in Tbilisi, Sep04)
Total
lt 1 GeV Original model OBE ?
Elastic

• gt 1 GeV Modified model
• original
• optical potential
• Reggezied vector meson

11
Selected Results NN Modeling above 1 GeV
R. Machleidt EDDA data (arXivnucl-th/0311002,20
03)
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Selected Results Status of NN models gt1 GeV

• SATURNE and EDDA Transition region (few GeV).
• NN model for transition region
• s reproduced, Spin observables gt 1 GeV wrong!
• Between 1 and 10 GeV serious problems!

R.Machleidt Defeat of Theory, Triumph of
Experiment. We need new ideas !
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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)
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Experiment ANKE
Cooler Synchrotron (COSY) Detector systems
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)
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NN Interaction np Amplitudes
?
dp?(pp)1S0 n
2
over a range in t
In collinear kinematics
Þ
(
)
(
)
(
)
17
Selected Results Test measurement of CE
Acceptance
COSY Deuteron Beam I 3 ? 109 ? fr
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Selected Results dp Reactions

• dp elastic
• dp?3Hep0
• dp?pspdp0
• Polarimetry, Luminosity

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Selected Results Spin dependent amplitudes
DSG, DT, APT from SAID
Bugg, Wilkin, NP A467(1987) 575
Method Works !!!
(
)
b
0
?
dp?(pp)1S0 n


)
(
15
.
0
86
.
1
ANKE
(
)
e
0
T20 0.39 0.04 (ANKE)
(
)
b
0


)
(
79
.
1
SAID
27
.
0
(
)
e
0
Value from SAID WI00 Error from R. Arndt
SE-Solution
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Selected Results NN program at ANKE

• Future polarized ANKE Experiments
• Charge-Exchange breakup
• np Elastic scattering
• Deuteron breakup

Talk S. Yaschenko
Strategy Begin commissioning of PIT using high
rate reactions that can be easily identified
(e.g. CE).
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Selected Results Meson Production
P. Winter et al., PLB, 544 (2002)

• ? production at COSY-11
• pp?pp? near threshold
• Single Polarization Ay
• distinguish different models
• ...... dominant ? exchange
• ___ p and ? exchange
• Double Polarization Cxx (Cyy)
• model independent extraction
• of amplitudes

?
dashed 1S0s final state dash-dotted
1S0s 3P0s dotted 1S0s 3P0s3P2s
K. Nakayama et al., PRC, 68 (2003)
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Experiments Current Facilities
Cooler Synchrotron (COSY) Detector systems
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Selected Results Meson Production
P. Winter et al., PLB, 544 (2002)

• ? production at COSY-11
• pp?pp? near threshold
• Single Polarization Ay
• distinguish different models
• ...... dominant ? exchange
• ___ p and ? exchange
• Double Polarization Cxx (Cyy)
• model independent extraction
• of amplitudes

?
dashed 1S0s final state dash-dotted
1S0s 3P0s dotted 1S0s 3P0s3P2s
K. Nakayama et al., PRC, 68 (2003)
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Selected Results YN Interaction

• Strangeness production at COSY-11
• Comparison of ? - and S0 production via pp ? p
  K?/S0 close to threshold
• Parameterisation includes
• Individual ? and S0 excitation functions
• p-Y final state interactions
• Hyperon production in pp ? pKL
• Production mechanism
• Next Double polarization? spin-dependence of Lp
• (ANKE, TOF)

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New Equipment WASA_at_COSY

• Symmetry and breaking (ISB, )
• Hadronic states spectroscopy (Q , )
• Baryon-baryon interaction (np, YN)
• Hadronic medium effects (Kaon mass)

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New Equipment PIT Spectator Telescope

• PIT Polarized Internal Target
• ABS
• Lamb-Shift Polarimeter
• Storage Cell
• Spectator Silicon telescope array

beam
Talk K. Grigoriev, Sec 8, Oct15
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New Equipment Polarized Target for TOF
Status and Outlook

• PT _at_ COSY-TOF
• (H. Dutz et al.,)
• PS185/3 _at_ 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

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Experiments Current Facilities
Cooler Synchrotron (COSY) Detector systems
29
New Equipment Polarized Target for TOF
Status and Outlook

• PT _at_ COSY-TOF
• (H. Dutz et al.,)
• PS185/3 _at_ 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

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Future Experiments Parity of ? (1540)
COSY is perfectly suited to determine the parity
free of any model!
Spin-correlation coefficient Axx in pp ???
neg. Parity
1
PLB,590,(2004),39-44
0
Axx
50
Q MeV
-1
pos. Parity
Talk Y. Uzikov, Sec 4, Oct14
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Conclusion
Existing Facilities ANKE, EDDA, COSY11 and TOF ?
pursue a strong spin physics program

• Single and Double Polarization Experiments
• NN Interaction (pn)
• YN Interaction
• pd Dynamics
• Meson Production in pp and pn Collisions
• Parity of T Pentaquark

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Observables np SAID data
APT (KLL) 600 MeV
DSG 600 MeV
DT (KNN) 600 MeV
APT (KLL) 800 MeV
DSG 800 MeV
DT (KNN) 800 MeV
APT (KLL) 900 MeV
DSG 900 MeV
DT (KNN) 800 MeV
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np SAID data Error analysis
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New Equipment Spectator Detector

• Features
• Three layers (double sided)
• 1st 60 ?m
• 2nd 300 ?m
• 3rd 5 mm
• Ekin2 MeV (60 MeV/c)
• 800 Channels
• Self-triggering
• On-board electronics
• UHV compatible
• Large Acceptance
• 10 per telescope
• 30 mm from the beam

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New Equipment Polarized Internal Target
Talk K. Grigoriev, Sec 8, Oct15

• Development for ANKE

Atomic Beam Source
Atomic Beam Intensity 7.41016 atoms/s (2 HFS)
Lamb-Shift Polarimeter
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Luminosity of ANKE PIT
Storage cell target requires a small ?-function
at the interaction point ?beamß½

I7.5?1016 H/s
dt I?L2?d-3?T-½
T300 K L350 mm a15 mm b20 mm
ANKE Luminosity (double polarized) Target
density (2.5 7.1)1013 cm-2 Beam
intensity 5109 particles Luminosity (2.0 -
5.7)1029 cm-2s-1
dt 2.51013 cm-2
a10 mm b12 mm
dt 7.11013 cm-2