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np Scattering Experiments at ANKE-COSY

np Scattering Experiments at ANKE-COSY. Forschungszentrum Jülich. Outline. COSY ( Co oler Sy nchrotron) at Jülich (Germany). Introduction Experimental Program NN-Scattering Experiments Charge – Exchange Reaction Experimental Facility Selected Results Outlook

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np Scattering Experiments at ANKE-COSY

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  1. np Scattering Experiments at ANKE-COSY Forschungszentrum Jülich

  2. Outline COSY (Cooler Synchrotron) at Jülich (Germany) • Introduction • Experimental Program • NN-Scattering Experiments • Charge–Exchange Reaction • Experimental Facility • Selected Results • Outlook • Summary • Hadronic probes: protons, deuterons • Polarization: beams & targets

  3. ANKE-COSY Program: An Overview Goal: Study of 3-body final states aiming to extract basic spin-dependent two-body scattering information Tools: • Hadronic probes (p,d) • Double polarization (beam/target) Topics: NN scattering ↔ np amplitudes, nuclear forces Meson production ↔ NN amplitudes (ChPT), FSI Strangeness production ↔ YN interaction, OZI rule Status: → → Towards the double polarization measurements ( dp - Nov’2009)

  4. (1) NN – Interaction

  5. NN-Interaction (I): General remarks pp elastic database • All labs with appropriate facilities have a duty to help to extend the NN database • Needed to understand the NN forces and to interpret the coupling to inelastic channels • Characterization requires precise data for Phase Shift Analyses • Thanks in large part to EDDA, there is a wealth of data for pp system d/d EDDA

  6. NN-Interaction (II): The EDDA Legacy • Ramping mode (Ep < 2.5 GeV) • Wide energy & angular range • High precision, consistency • for pp (I=1)-system: • ds/dWPRL 78 (1997); EPJ A 22 (2004) • AN PRL 85 (2000); EPJ A 23 (2005) • A**PRL 90 (2003); PR C 71 (2005) • Full characterization of elastic pp scattering (PWA)  No dibaryon signal

  7. NN-Interaction (III): np database np charge exchange d/d Current experimental status • R. Arndt: • “Gross misconception within the community that np amplitudes are known to a couple of GeV” • “np data above 800 MeV is a DESERT for experimentalists” npsystem poorly known →ANKE is providing high-quality data in forward/backward region np forward np charge-exchange Ayy np forward

  8. dp→psp (np) → → pd→psp (pn) np forward NN-Scattering (I): np elastic (small angle) p → d beam: → → → d target: d ↑ n p D ↑ p d beam: up to 1.1 GeV np d target: up to 2.8 GeV pn ↑ psp n dp observables: d/d, T20,T22, Ay,y, ... quasi-free np observables:Ay, Ayy

  9. np charge-exchange NN-Scattering (II): np elastic (large angle) n → d beam: → dp→(pp)1S0n → d target: → → pd→(pp)1S0n → d ↑ n p D ↑ p d beam: up to 1.1 GeV np d target: up to 2.8 GeV pn ↑ psp ↓ p dp observables: d/d, T20,T22, Ay,y, ... quasi-free np observables:Ay, Ayy

  10. np-Scattering (I): Deuteron Charge-Exchange p p’ In impulse approximation, the pd  n {pp} amplitude corresponding to the figure  M = <k,m1,m2,m3|f13eiq.r/2|d,m,m3> k = pp relative momentum in final state. q = momentum transfer from p to n. Epp = excitation energy in final pp state. np charge-exchange amplitudes in cm: with basis vectors in terms of initial and final cm momenta p and p': D.V.Bugg & C.W., Nucl.Phys.A467 (1987) 575

  11. 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 b Þ g + 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 np-Scattering (II): Deuteron Charge-Exchange → → dp→(pp)1S0 n 2 over a range int In collinear kinematics Þ ( ) ( ) ( )

  12. COSY Facility Characteristics: • Energy range: • 0.045 – 2.8 GeV (p) • 0.023 – 2.3 GeV (d) • Max. momentum ~ 3.7 GeV/c • Energy variation (ramping mode) • Electron and Stochastic cooling • Internal and external beams • High polarization (p,d) • Spin manipulation

  13. Atomic Beam Source Polarized Internal Target (PIT) Silicon Telescope System Silicon Telescope Lamb-Shift Polarimeter Spectator detector Exp. Facility (I): ANKE detection system Spectator detection

  14. Exp. Facility (II): Polarized Internal Gas Target • Main componentsofPIT: • Atomic Beam Source (ABS) • H orD • H beam intensity (2 HFS) • 8 ∙1016 atoms/s • Beam size at the IP • σ = 2.85 ± 0.42 mm • Polarization for Hydrogen • PZ = 0.89 ± 0.01 • PZ = -0.96 ± 0.01 • Lamb-Shift Polarimeter (LSP) • Storage Cell (SC) in target chamber

  15. Selected Results from ANKE-COSY

  16. n → → dp→{pp}S (00)+n → → d ↑ n p D ↑ p ↑ psp ↓ p np-Scattering (II): Measurements at ANKE • np system: different isospin channel • via Charge-Exchange deuteron breakup: Measurements: • at Tn up to 1.15 GeV for np • (Td=1.6, 1,8, 2.3 GeV) Epp < 3 MeV

  17. A A A P P yy xx y z zz Selected Results (I): Polarimetry reactions Td =1.2 GeV (Tn=585 MeV) dp → dp Pz, Pzz np → dπ0  Pz dp → 3Heπ0 Pzz → → → Pz≈75% Pzz ≈60% with EDDA and LEP

  18. Selected Results (II): Beam polarization dp → dp ANKE ANKE dp → 3Heπ0 np → dπ0 dp → (pp)n SAID (Tn = 585 MeV) ANKE ANKE Depolarization less then 4% D. Chiladze et al. Phys. Rev. STAB , 9 (2006)

  19. byI = byIII Energy ramping 1.8 GeV byyI = byyIII II 1.2 GeV 1.2 GeV I III Selected Results (III): Polarization export • Experiments at higher energies uses polarization export technique • Data has been taken at Td =1.6, 1.8,and 2.23 GeV Result byI = -0.213 ± 0.005 byIII = -0.216 ± 0.006 byyI = 0.057 ± 0.003 byyIII = 0.059 ± 0.003 Time

  20. d 2 2 2 2       , T , T , , 20 22 dq Selected Results (IV): Analysing powers, Cross sec. → D.Chiladze et al. PLB 637, 170 (2006) dp→{pp}1S0 n Axx (T22) Transition from deuteron to {pp}1S0:pn  np spin flip np spin-dependent amplitudes: Results: • Method works at Tn = 585 MeV • Application to higher energies • Td=1.6, 1.8, 2.23 GeV (in progress) Td = 1170 MeV Ayy (T20) D.Chiladze et al. EPJA,40, 23 (2009) New ! Tn = 585 MeV SAID np amplitudes

  21. d 2 2 2 2       , T , T , , 20 22 dq Selected Results (V): Spin amplitudes → dp→{pp}1S0 n Epp <1 Mev Transition from deuteron to {pp}1S0:pn  np spin flip np spin-dependent amplitudes: Results at q=0: t20 (q=0) = 0.37 ± 0.02 SAID prediction = 0.58 D.Chiladze et al. EPJA,40, 23 (2009)

  22. d 2 2 2 2       , T , T , , 20 22 dq → → dp Selected Results (VI): Spin correlations → D.Chiladze et al. PLB 637, 170 (2006) dp→{pp}1S0 n Axx (T22) Transition from deuteron to {pp}1S0:pn  np spin flip np spin-dependent amplitudes: Results: • Method works at Tn = 585 MeV • Application to higher energies • Td=1.6, 1.8, 2.23 GeV (in prog.) Next step: • Double polarized → Cy,y, Cx,x=> relative phases Td = 1170 MeV Ayy (T20) Cy,y Cx,x Production run for double polarization measurements: Nov.’2009

  23. Outlook: Double polarization High target polarization Qy ~ 80% by nuclear reaction np → dπ0 Online monitoringof ABS polarization by Lamb-shift polarimeter Silicon Tracking Telescope – as a tool for Polarimetry operating with storage cell → → dp – test experiment at ANKE L ≥2 x 1029 s-1cm-2 achieved at COSY

  24. Summary • COSY- unique opportunities for hadron physics withpolarized hadronic probes (beam & target) • Deuteron breakup reaction successfully used as a method to study np charge-exchange amplitudes - proof of principal is achieved ! • The method suggests that measurements at higher energies will provide useful information in regions where the existing np database is far less reliable • ANKE equipment has been commissioned and it ready for extraction of spin correlation parameters • Use of inverse kinematics with a polarized proton incident on a polarized deuteron will extend study up to max. COSY energy 2.9 GeV

  25. The END Thank you very much for your – attention – Many thanks to the organizers !

  26. np-Scattering: Deuteron Charge-Exchange Unpolarized np  pn differential cross section: As first approximation, consider data with Epp < 3 MeV; 1S0 dominance. There are two form factors from the integral over the Fermi momenta: S+ and S- are longitudinal (=0) and transverse ( = 1) form factors. In terms of the wave functions of the deuteron S- and D-states, u and w, and the 1S0pp wave functionk,

  27. np-Scattering: Deuteron Charge-Exchange Define a ratio of form factors by unpolarized intensity depends only upon spin-flip amplitudes: Terms can be separated by measuring with polarised beams/targets: unpolarized cross section  d,p vector analysing powers  d tensor analysing powers  d-p vector spin correlations  d-p tensor spin correlation 

  28. DSG, DT, APT from SAID ( ) ( ) 2 2 b - e 0 0 = T 2 ( ) ( ) 20 2 2 b + e 2 0 0 → dp→(pp)1S0 n ( ) 2 e(0) = + - 4 DSG 1 APT 2 DT T20 = 0.39 ± 0.04 (ANKE) ( ) 2 b(0) = - 4 DSG 1 APT Bugg, Wilkin, NP A467(1987) 575 ( ) b 0 = ± 1 . 86 0 . 15 (ANKE) ( ) e 0 ( ) b 0 = ± 1 . 79 (SAID) 0 . 27 ( ) e 0 Value from SAID WI00 Error from R. Arndt SE-Solution

  29. COSY-Hardware (III): Silicon Tracking Telescope 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

  30. Future plans: Experiments with polarized probes 2005-2009 2010-2014 COSY proposal #152 ArXiv:nucl-ex/0511028

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