High Energy Physics Institute of Tbilisi State University IKP, Forschungszentrum Jülich

1. High Energy Physics Institute of Tbilisi State University IKP, Forschungszentrum Jülich Recent Results of the Analysing Power Measurement for the dp → (pp)n Charge-Exchange Reaction at ANKE/COSY → David Mchedlishvili 1st October, 2010

2. d/d Ayy NN database: np Scattering data • Current experimental status of np data • ANKE is able to improve np database np charge-exchange np charge-exchange ANKE range ANKE range np forward np forward

3. → → dp→(pp)1S0n NN interaction: npScattering(large angles) n → → d ↑n np charge exchange measures directly magnitudes of differences of pp and np elastic amplitudes p D ↑p ↑psp ↓p At small excitation energies in the final pp system 1S0 state Hence there is a spin-flip from 3S1,3D1 of the deuteron to 1S0 of the diproton. Data sensitive to spin-flip, isospin-flip transitions.

4. dp→(pp)1S0n: Spin observables Unpolarised intensity depends only upon spin-flip amplitudes: Define a ratio of form factors by Terms can be separated by measuring with polarized beams/targets: d and p vector analysing powers Unpolarised cross section d tensor analysing powers d-p vector spin correlations d-p tensor spin correlation D.V.Bugg & C.W., Nucl.Phys.A467 (1987) 575

5. Proof of principle at 1.17 GeV Results: • Method works at Tn = 585 MeV • Application to higher energies Td=1.6, 1.8, 2.27 GeV D.Chiladze et al. PLB 637, 170 (2006) D.Chiladze et al. EPJA,40, 23 (2009) Tn = 585 MeV SAID np amplitudes

6. Results eyI = eyIII Energy ramping eyI = -0.213 ± 0.005 2.27 GeV eyIII = -0.216 ± 0.006 eyyI = eyyIII II eyyI = 0.057 ± 0.003 1.2 GeV 1.2 GeV eyyIII = 0.059 ± 0.003 I III Charge-exchange study at higher energies Polarised beam, unpolarised target: Beam polarimetry at Td=1.2 GeV Polarisation export technique Tensor analysing powers at Td=1.6, 1.8, 2.27 GeV Cross section Double polarised experiment: Spin correlation coefficients (see talk by D.Chiladze)

7. Polarised deuteron beam at Td=1.2, 1.6, 1.8, 2.27 GeV Unpolarised hydrogen cluster target Eight configurations of the polarised deuteron ion source Experimental setup Higher Energy 1.2 GeV t

8. Reaction identification at 1.2 GeV dp→(pp)n andnp→dπ0reactions provide double track events in forward detector: • pp from dp→(pp)n • dpspfrom quasi-freenp→dπ0 ∆tmeas [ns] Fast pp pairs are distinguished from dpsp using time of flight method ∆ttof [ns]

9. Beam polarimetry Beam polarisation is measured at Td = 1.2 GeVandis assumed to be unchanged at higher energies • np→dπ0Pz • dp→(pp)nPzz → → → dp→(pp)nreaction normalised count ratio for low excited pp pairs (Epp< 3 MeV): → np→dπ0reaction normalised count ratio: Pz up to 70% Pzz up to 80%

10. Consistency check Determination of Axx and Ayy values for different transferred momentum at Td= 1.2 GeVbeam energy to check the reliability of the analyses Analysing powers at Td = 1.2 GeVcorrespond well to the theoretical predictions Application to higher energies using polarisation export technique

11. Reaction identification at 2.27 GeV Same methods are used at higher energies: Reaction identification by using time of flight method Use cuts on missing mass spectra Tensor analysing powers from dp→(pp)n reaction ∆tmeas [ns] n(0.939) ∆0(1.232) ∆ttof [ns]

12. Analysing powers at higher energies New! New! Td = 1.6 GeV Td = 2.27 GeV New! Td = 1.8 GeV Results differ from theory at Td=2.27 GeV, especially for low transferred momentum region

13. Amplitude behavior Td = 2.27 GeV Td = 1.2 GeV |ε|tends to decrease drastically with energy increase

14. → dp→(pp)1S0∆0 Td = 2.27 GeV ∆0 peak is well observed on missing mass spectra of proton-proton pairs Good possibility for further investigation of the spin structure of the nucleon-nucleon interaction ∆0 Mass is taken: m∆=1232±50 MeV/c2 SATURNE at Td = 2 GeV ANKE at Td = 2.27 GeV Polarisation response: SATURNE data ANKE results are consistent with SATURNE data

15. Analysing power behavior in case of ∆0 First measurements at Td = 2.27 GeV ! Significant differences: • Tensor analysing power signs are flipped • Axx and Ayy tend to be zero at low momentum transfer PRELIMINARY Theoretical explanation of such behavior of tensor analysing powersis needed!

16. Summary THANK YOU • Beam polarimetry has been done successfully at 1.2 GeV • Polarisation export technique is used at higher energies • dp→(pp)n tensor analysing powers have been measured at energies up to 2.27 GeV • Firs results of tensor analysing powers for dp→(pp)∆0channel have been obtained at Td = 2.27 GeV Outlook • Further investigation of charge-exchange channel with delta production • Spin correlation coefficient analyses using double polarised experimental data from November 2009 beam time (Td = 1.2, 2.27 GeV)