Spin Physics of NN Interactions at COSY Andro

Spin Physics of NN Interactions at COSY Andro Kacharava Universität Erlangen 16 th SPIN Symposium, Trieste, October 10_16, 2004 Andro Kacharava Spin Physics at COSY 1

Outline • Experiments at COSY • NN Interaction • Selected Results • NN Elastic • Meson Production • YN Interaction • New Equipment • Conclusion Spin Physics at COSY 2

Experiments: COSY Accelerator COoler SYnchrotron: Ions: (pol. + unpol. ) p and d Momentum: 300 to 3700 Me. V/c. . . unique possibilities: - Spin Manipulation - Electron Cooling at Injection - Stochastic Cooling >1. 5 Ge. V/c Targets: - Internal: Solid, Cluster, Polarized Atomic - External: Solid, Liquid Spin Physics at COSY 3

Experiments: Current Facilities COSY EDDA COSY-11 ANKE TOF Cooler Synchrotron (COSY) & Detector systems Spin Physics at COSY 4

NN Interaction • Fundamental for strong interaction. • Characterization requires precise data for PSA. • pp system: up to 2. 5 Ge. V 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 Ge. V. J. Bystricky: Measurements of ANY observables at small angle are highly desirable to improve PSAs. Spin Physics at COSY 5

NN Interaction: Observables Storage rings - unique environment for double-polarized experiments. dσ/d = I 0 ·[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 6

Selected Results: pp elastic at EDDA Characterization of NN-interaction • Large kinematical range: 1. 0 -3. 3 Ge. V/c, 30°-90° [c. m. ] T=2. 1 Ge. V • High precision data - Unpolarized, single, double polarized. - Large impact on pp PSA >500 Me. V. • Further Results: • No Evidence for dibaryons • Polarimetry for the pp system F. Bauer et al. , PRL 90 (2003) Spin Physics at COSY 7

Experiment: EDDA COSY-11 ANKE TOF Cooler Synchrotron (COSY) & Detector systems Spin Physics at COSY 8

Selected Results: pp elastic at EDDA Characterization of NN-interaction • Large kinematical range: 1. 0 -3. 3 Ge. V/c, 30°-90° [c. m. ] T=2. 1 Ge. V • High precision data - Unpolarized, single, double polarized. - Large impact on pp PSA >500 Me. V. • Further Results: • No Evidence for dibaryons • Polarimetry for the pp system F. Bauer et al. , PRL 90 (2003) Spin Physics at COSY 9

Selected Results: NN Modeling above 1 Ge. V R. Machleidt (workshop in Tbilisi, Sep’ 04) Total Original model < 1 Ge. V: Original model – OBE + Δ Elastic Modified model > 1 Ge. V: Modified model original + optical potential + Reggezied vector meson Spin Physics at COSY 10

Selected Results: NN Modeling above 1 Ge. V R. Machleidt & EDDA data (ar. Xiv: nucl-th/0311002, 2003) modified original PSA (VPI) Spin Physics at COSY 11

Selected Results: Status of NN models >1 Ge. V • SATURNE and EDDA: Transition region (few Ge. V). • NN model for transition region: - σ reproduced, Spin observables > 1 Ge. V wrong! - Between 1 and 10 Ge. V serious problems! R. Machleidt: Defeat of Theory, Triumph of Experiment. We need new ideas ! Spin Physics at COSY 12

Selected Results: np elastic at ANKE • Spin structure of np→pn reaction amplitudes • Method: Spin filter →→ dp→(pp)1 S 0 n • Next Step: Measurement of spin observables for pn system up to 3 Ge. V • Method: Spectator technique →→ pd→psp (pn) Spin Physics at COSY 13

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

Selected Results: np elastic at ANKE • Spin structure of np→pn reaction amplitudes • Method: Spin filter →→ dp→(pp)1 S 0 n • Next Step: Measurement of spin observables for pn system up to 3 Ge. V • Method: Spectator technique →→ pd→psp (pn) Spin Physics at COSY 15

NN Interaction: np Amplitudes → dp→(pp)1 S 0 n S (k , q 2 ) Ι= g +β +ε +δ R , R= ; S (k , q 2 ) 2 2 2 d 4 s 1 - ( ) = [ ] I S k , q / 2 ; 3 dtd k 3 + 2 [ ] ICy, y = -2 (e *d )R ; ICx, x = -2 (b *e ) ; IT 20 = 2 2 1 g + b + d R 2 - 2 e ; 2 IT 22 = 2 2 ds , T 20 , T 22 g + b , d , e dt In collinear kinematics ] ICz, z = -2 (d *b )R. over a range in [ I = 2 b + e ; IT 20 = 2 b - e 2 [ 2 2 3 2 g + b - d R 2; 2 2 2 ]Þ 2 t b, e ICy, y = -2 (eb *); ICxz, y = -3Á(be *) Þ cos(je - jb ) Spin Physics at COSY 16

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

Selected Results: dp Reactions • • • dp elastic dp→ 3 Hep 0 dp→pspdp 0 • Polarimetry, Luminosity dp→(pp)n Spin Physics at COSY 18

Selected Results: Spin dependent amplitudes 4 e(0) 2 = DSG (1 + APT - 2 DT ) 4 b(0) 2 = DSG ( 1 - APT ) ! ! ! s k b (0 ) - e (0 ) r T = 2 o 2 b (0 ) + e (0 ) W d o b (0 ) dp→(pp) t nh = 1. 86 ± 0. 15 e (0 ) e T = 0. 39 M ± 0. 04 (ANKE) b (0 ) DSG, DT, APT from SAID Bugg, Wilkin, NP A 467(1987) 575 2 20 2 2 2 → 1 S 0 ( ANKE) 20 e (0 ) = 1. 79 ± 0. 27 ( SAID) Value from SAID WI 00 Error from R. Arndt SE-Solution Spin Physics at COSY 19

Selected Results: NN program at ANKE Future polarized ANKE Experiments: →→ 1. Charge-Exchange breakup dp→(pp)1 S 0 n 2. np Elastic scattering 3. Deuteron breakup →→ pd→psp(pn) →→ pd →(pp)1 S 0 n Talk S. Yaschenko Strategy: Begin commissioning of PIT using high rate reactions that can be easily identified (e. g. CE). Spin Physics at COSY 20

Selected Results: Meson Production P. Winter et al. , PLB, 544 (2002) • 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 extraction of amplitudes: 1 S s final state dashed: 0 dash-dotted: 1 S 0 s + 3 P 0 s 1 S s + 3 P s +3 P s dotted: 0 0 2 Spin Physics at COSY K. Nakayama et al. , PRC, 68 (2003) 21

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

Selected Results: Meson Production P. Winter et al. , PLB, 544 (2002) • 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 extraction of amplitudes: 1 S s final state dashed: 0 dash-dotted: 1 S 0 s + 3 P 0 s 1 S s + 3 P s +3 P s dotted: 0 0 2 Spin Physics at COSY K. Nakayama et al. , PRC, 68 (2003) 23

Selected Results: YN Interaction • Strangeness production at COSY-11 • Comparison of Λ - and Σ 0 – production via pp p K+Λ/Σ 0 close to threshold • Parameterisation includes: • Individual Λ and Σ 0 excitation functions • p-Y final state interactions • Hyperon production in pp p. K+L: • Production mechanism • Next: Double polarization spin-dependence of Lp (ANKE, TOF) Spin Physics at COSY 24

New Equipment : WASA@COSY • Symmetry and –breaking (ISB, …) • Hadronic states spectroscopy • Baryon-baryon interaction • Hadronic medium effects Spin Physics at COSY (Q+ , …) (np, YN) (Kaon mass) 25

New Equipment: PIT & Spectator Telescope PIT: Polarized Internal Target: : - ABS - Lamb-Shift Polarimeter - Storage Cell Spectator: Silicon telescope array be am Talk K. Grigoriev, Sec 8, Oct’ 15 Spin Physics at COSY 26

New Equipment: Polarized Target for TOF Status and Outlook PT @ COSY-TOF (H. Dutz et al. , ) o o o PS 185/3 @ 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 27

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

New Equipment: Polarized Target for TOF Status and Outlook PT @ COSY-TOF (H. Dutz et al. , ) o o o PS 185/3 @ 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 29

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 4), 0 0 , (2 , 590 PLB Axx 4 39 -4 neg. Parity 0 50 Q [Me. V] -1 pos. Parity Talk Y. Uzikov, Sec 4, Oct’ 14 Spin Physics at COSY 30

Conclusion Existing Facilities ANKE, EDDA, COSY 11 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 31

Observables: np SAID data DSG 600 Me. V APT (KLL) 600 Me. V DT (KNN) 600 Me. V DSG 800 Me. V APT (KLL) 800 Me. V DT (KNN) 800 Me. V DSG 900 Me. V APT (KLL) 900 Me. V DT (KNN) 800 Me. V Spin Physics at COSY 32

np SAID data: Error analysis Spin Physics at COSY 33

New Equipment: Spectator Detector Features: – Three layers (double sided) 1 st: 60 m 2 nd: 300 m 3 rd: 5 mm – Ekin~2 Me. V (60 Me. V/c) – 800 Channels – Self-triggering – On-board electronics – UHV compatible – Large Acceptance • 10% per telescope • 30 mm from the beam Spin Physics at COSY 34

New Equipment: Polarized Internal Target Talk K. Grigoriev, Sec 8, Oct’ 15 • Development for ANKE Atomic Beam Source Atomic Beam Intensity 7. 4· 1016 atoms/s (2 HFS) Lyman- Spectrum Lamb-Shift Polarimeter Spin Physics at COSY 35

Luminosity of ANKE PIT Storage cell target requires a small -function at the interaction point: beam~β½ I I=7. 5 1016 H/s d L beam dt ~ I L 2 d-3 T-½ dt =2. 5· 1013 cm-2 T=300 K L=350 mm a=15 mm b=20 mm dt =7. 1· 1013 cm-2 a=10 mm b=12 mm Spin Physics at COSY 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-2 s-1 36