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Spin Physics of NN Interactions at COSY Andro Kacharava Universität Erlangen

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.

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Spin Physics of NN Interactions at COSY Andro Kacharava Universität Erlangen

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  1. Spin Physics of NN Interactions at COSY Andro Kacharava Universität Erlangen 16th SPIN Symposium, Trieste, October 10_16, 2004 Andro Kacharava 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 ... uniquepossibilities: - 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. COSY EDDA COSY-11 ANKE TOF Experiments: Current Facilities Cooler Synchrotron (COSY) & Detector systems 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 Storage rings -unique environment for double-polarized experiments. 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 N = y S = x L = z 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. COSY EDDA COSY-11 ANKE TOF Experiment: EDDA Cooler Synchrotron (COSY) & Detector systems 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 Modified model Original model > 1 GeV: Modified model original + optical potential + Reggezied vector meson R.Machleidt (workshop in Tbilisi, Sep’04) Total < 1 GeV: Original model – OBE + Δ Elastic Spin Physics at COSY

  11. Selected Results: NN Modeling above 1 GeV modified original PSA (VPI) R. Machleidt & EDDA data (arXiv:nucl-th/0311002,2003) 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 → → dp→(pp)1S0 n • Spin structure of np→pnreaction amplitudes • Method: Spin filter • Next Step: Measurement of spin observables for pnsystem up to 3 GeV • Method: Spectator technique → → pd→psp (pn) Spin Physics at COSY

  14. COSY EDDA COSY-11 ANKE TOF Experiment: ANKE Cooler Synchrotron (COSY) & Detector systems Spin Physics at COSY

  15. Selected Results: np elastic at ANKE → → dp→(pp)1S0 n • Spin structure of np→pnreaction amplitudes • Method: Spin filter • Next Step: Measurement of spin observables for pnsystem up to 3 GeV • Method: Spectator technique → → pd→psp (pn) Spin Physics at COSY

  16. NN Interaction: npAmplitudes s 4 d 1 [ ] ( ) ( ) 2 + - = S k , q 2 I S k , q / 2 ; 2 2 2 2 = = Ι + + + g 2 R ; 3 β ε δ R , 3 dtd k ( ) - S k , q 2 [ ] 1 [ ] 3 2 2 2 2 = g + b + d - e 2 2 2 2 2 IT R 2 ; = g + b - d IT R ; 20 22 2 ( ) ( ) ( ) = - e d = - b e = - d b * * * IC 2 R ; IC 2 ; IC 2 R.    y , y x , x z , z s d 2 2 2 2 Þ g + b d e , T , T , , 20 22 dt [ ] 2 2 2 2 = b + e = b - e Þ b e I 2 ; IT 2 , 20 = - eb = - be Þ j - j * * IC 2 ; IC 3 cos  Á e b y , y xz , y → dp→(pp)1S0 n 2 over a range int In collinear kinematics Þ ( ) ( ) ( ) Spin Physics at COSY

  17. Selected Results: Test measurement of CE Acceptance COSY Deuteron Beam I = 3  109  fr Spin Physics at COSY

  18. Selected Results: dp Reactions dp elastic dp→3Hep0 dp→pspdp0 Polarimetry, Luminosity dp→(pp)n Spin Physics at COSY

  19. Selected Results: Spin dependent amplitudes ( ) ( ) 2 2 b - e 0 0 = T 2 ( ) ( ) 20 2 2 b + e 2 0 0 ( ) 2 e(0) = + - 4 DSG 1 APT 2 DT ( ) 2 b(0) = - 4 DSG 1 APT DSG, DT, APT from SAID Bugg, Wilkin, NP A467(1987) 575 Method Works !!! ( ) b 0 → dp→(pp)1S0 n = ± 1 . 86 0 . 15 ( ANKE ) ( ) e 0 T20 = 0.39 ± 0.04 (ANKE) ( ) b 0 = ± 1 . 79 ( SAID ) 0 . 27 ( ) e 0 Value from SAID WI00 Error from R. Arndt SE-Solution Spin Physics at COSY

  20. Selected Results: NN program at ANKE → → dp→(pp)1S0 n → → pd→psp(pn) → → pd →(pp)1S0 n 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). Spin Physics at COSY

  21. Selected Results: Meson Production P. Winter et al., PLB, 544 (2002) • η productionatCOSY-11 pp→ppη near threshold Single Polarization: Ay distinguish different models ......dominant ρ exchange ___ π and η exchange Double Polarization: Cxx (Cyy) model independentextraction of amplitudes: → dashed: 1S0s final state dash-dotted: 1S0s + 3P0s dotted: 1S0s + 3P0s+3P2s K. Nakayama et al., PRC, 68 (2003) Spin Physics at COSY

  22. COSY EDDA COSY-11 ANKE TOF Experiments: Current Facilities Cooler Synchrotron (COSY) & Detector systems Spin Physics at COSY

  23. Selected Results: Meson Production P. Winter et al., PLB, 544 (2002) • η productionatCOSY-11 pp→ppη near threshold Single Polarization: Ay distinguish different models ......dominant ρ exchange ___ π and η exchange Double Polarization: Cxx (Cyy) model independentextraction of amplitudes: → dashed: 1S0s final state dash-dotted: 1S0s + 3P0s dotted: 1S0s + 3P0s+3P2s K. Nakayama et al., PRC, 68 (2003) Spin Physics at COSY

  24. Selected Results: YN Interaction • Strangeness production atCOSY-11 • Comparison of Λ - and Σ0 – production via pp  p K+Λ/Σ0 close to threshold • Parameterisationincludes: • Individual Λ and Σ0 excitation functions • p-Y final state interactions • Hyperon production in pp  pK+L: • Production mechanism • Next:Double polarization spin-dependence of Lp (ANKE, TOF) Spin Physics at COSY

  25. New Equipment: WASA@COSY • Symmetry and –breaking(ISB, …) • Hadronic states spectroscopy(Q+ , …) • 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 beam Talk K. Grigoriev, Sec 8, Oct’15 Spin Physics at COSY

  27. New Equipment: Polarized Target for TOF Status and Outlook 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 Spin Physics at COSY

  28. COSY EDDA COSY-11 ANKE TOF Experiments: Current Facilities Cooler Synchrotron (COSY) & Detector systems Spin Physics at COSY

  29. New Equipment: Polarized Target for TOF Status and Outlook 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 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++ neg. Parity +1 PLB,590,(2004),39-44 0 Axx 50 Q [MeV] -1 pos. Parity Talk Y. Uzikov, Sec 4, Oct’14 Spin Physics at COSY

  31. 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 Θ+ Pentaquark Spin Physics at COSY

  32. 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 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 m 2nd: 300 m 3rd: 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 Lyman- Spectrum Talk K. Grigoriev, Sec 8, Oct’15 • Development for ANKE Atomic Beam Source Atomic Beam Intensity 7.4·1016 atoms/s (2 HFS) Lamb-Shift Polarimeter Spin Physics at COSY

  36. Luminosity of ANKE PIT I d beam L Storage cell target requires a small -function at the interaction point: beam~β½ I=7.51016 H/s dt ~ IL2d-3T-½ T=300 K L=350 mm a=15 mm b=20 mm dt =2.5·1013 cm-2 ANKE Luminosity (double polarized) Target density: (2.5 – 7.1)·1013 cm-2 Beam intensity: 5·109 particles Luminosity: (2.0 - 5.7)·1029 cm-2s-1 a=10 mm b=12 mm dt =7.1·1013 cm-2 Spin Physics at COSY

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