1. Mitglied der Helmholtz-Gemeinschaft TSU HEPI Double-polarised np-scattering experiments at ANKE David Mchedlishvili for the ANKE collaboration HEPI, Tbilisi State University IKP, Forschungszentrum Jülich July 8, 2014

2. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI Outline: o Introduction o Experimental facility o Impulse approximation o Experiments o Results o Summary and Outlook NN pp np dp pd 1.Unpolarised 2.Single polarised 3.Double polarised 1.Unpolarised 2.Single polarised 3.Double polarised

3. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI Existing np scattering data d  /d  A yy  Current experimental status of np data np forward np charge-exchange np forward ANKE ANKE is able to provide the experimental data for pp and np systems at up to 2.8 GeV and improve our understanding of NN interaction

4. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI 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 polarisation (p,d) Spin manipulation COSY (COoler SYnchrotron) at Jülich (Germany) Experimental facility: COSY storage ring

5. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI STT Apparatus: ANKE spectrometer Main features:  Excellent Kaon identification (Positive and Negative)  Low energy proton (spectator) detection (STT)  Di-proton ({pp} s ) selection (by FD)  Polarized (unpolarized) dense targets Main features:  Excellent Kaon identification (Positive and Negative)  Low energy proton (spectator) detection (STT)  Di-proton ({pp} s ) selection (by FD)  Polarized (unpolarized) dense targets S. Barsov et al., NIM A 462, 364 (1997)

6. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI Polarised internal gas target at ANKE 1.Atomic Beam Source (ABS) 2.Lamb-shift Polarimetry 3.Cell: 20 x 15 x 370 mm 3 Benefit from cell: I.Increased target density by factor of ≈100 (up to 10 13 cm -2 ) Drawback: I.Dedicated beam development II.Background handling III.Vertex reconstruction in analyses COSY beam

7. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI np Scattering at ANKE p p n p Small cm scattering angles (np forward) Large cm scattering angles (np charge-exchange) “Diproton” {pp} p p n p p n p n p n p p p n p n p p p n

8. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI Impulse approximation dp → {pp} 1 S 0 n ƒ np→pn (SAID) F.F. is evaluated with PARIS wave function 1S01S0 Transition F.F. ~ np charge-exchange amplitudes in cm: with basis vectors in terms of initial and final cm momenta p and p':

9. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI dp→{pp} 1 S 0 n: Spin observables Define a ratio of form factors by Terms can be separated by measuring with polarized beams/targets: Unpolarised cross section d and p vector analysing powers d tensor analysing powers d-p vector spin correlations d-p tensor spin correlation Unpolarised intensity depends only upon spin-flip amplitudes: D.V.Bugg & C.W., Nucl.Phys.A467 (1987) 575

10. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI dp → {pp}X reaction channels dp→{pp}X: T d =1.2GeV T d =2.27GeV dp→{pp} s ndp→{pp} s ∆ 0 Valuable information on the modelling of the np→p∆ 0 amplitudes Data sensitive to the np→pn elastic amplitudes (large cm angles)

11. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI dp → {pp} s n: A y p, C y,y, C x,x T d = 1.2 GeV T d = 2.27 GeV T d = 1.2 GeV T d = 2.27 GeV Problem with reduced by 25% D.Mchedlishvili et al. EPJA, 49, 49 (2013) → → E pp < 3 MeV

12. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI dp → {pp} s n: dσ/dq, A xx, A yy T d = 1.6 GeV (800 MeV/A) T d = 1.8 GeV (900 MeV/A) T d = 2.27 GeV (1135 MeV/A) reduced by 25% D.Mchedlishvili et al. EPJA, 49, 49 (2013) E pp < 3 MeV →

13. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI Polarised deuteron target commissioning Unpolarised proton beam at T p = 600 MeV Polarised deuteron cell target, with vector and tensor polarisations. 10 days of data taking. Solid state spectator detectors are involved to extend the ANKE capabilities. Maximum COSY energy: T d = 2.3 GeV (1.15 GeV/nucleon) vs T p = 2.8 GeV pd experiments: Extension of np program in inverse kinematics pd experiments: Extension of np program in inverse kinematics

14. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI Deuteron breakup in inverse kinematics pd → {pp}n at T p = 600 MeV Two different region: 1.pp in same side of STT small E pp, large q 2.pp in oposite side of STT large E pp, small q →

15. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI pd → {pp} s n: A y d, A yy Will be submitted to Phys. Lett. B FDSTT pd → {pp} s ndp → {pp} s n → → T p = 600 MeV E pp < 3 MeV STT data: = 0.9 no A xx signal! → A y d ≈ 0 as predicted in impulse approximation for small E pp

16. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI Future studies Upcoming pd experiment at ANKE:  Polarised proton beam at 0.6, 1.135, 1.3 and 1.8 GeV  Polarised deuterium target from the ABS Primary aims: 1.Tensor analysing powers (A xx, A yy ) and spin correlation parameters (C x,x, C y,y ) in the pd → {pp} s X reaction (X=n, X=∆ 0 ). Opportunity to study the ∆ polarisation by detecting the decay products in ANKE 2.Spin correlation parameters (A x,x, A y,y ) for quasi-free pn elastic. Due to the Fermi motion, several energy intervals will be produced at given beam energy in the angular range 5° < θ cm < 40°. → →

17. David Mchedlishvili Double-polarised np-scattering experiments at ANKE July 8, 2014 TSUHEPI Summary np→d π 0 observables:  A x,x, A y,y at T n = 600 MeV. D.Mchedlishvili et al. PLB 726, 634 (2013) dp→{pp} s n observables:  dσ/dq, A xx, A yy at T d = 1.2, 1.6, 1.8, 2.27 GeV  A y p, C x,x, C y,y at T d = 1.2, 2.27 GeV dp→{pp} s ∆ 0 observables:  dσ/dm, A xx, A yy at T d = 1.6, 1.8, 2.27 GeV D.Mchedlishvili et al. EPJA, 49, 49 (2013) D.Mchedlishvili et al. PLB 726, 145 (2013)  pd→{pp} s X (X=n, X=∆ 0 ) observables:  A y p, A y d, A xx, A yy, C x,x, C y,y at T p = 1.3, 1.8 GeV  A y p at T p = 0.8, 1.6, 1.8, 2.0, 2.2, 2.4 GeV pd→{pp} s n observables:  A y d, A yy at T p = 600 MeV (T d = 1.2 GeV equivalent). Will be submitted to PLB