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Mitglied der Helmholtz-Gemeinschaft TSU HEPI Double-polarised np-scattering experiments at ANKE David Mchedlishvili for the ANKE collaboration HEPI, Tbilisi.

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Presentation on theme: "Mitglied der Helmholtz-Gemeinschaft TSU HEPI Double-polarised np-scattering experiments at ANKE David Mchedlishvili for the ANKE collaboration HEPI, Tbilisi."— Presentation transcript:

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: – 2.8 GeV (p) – 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 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


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