Mitglied der HelmholtzGemeinschaft TSU TBILISI STATE UNIVERSITY The

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Mitglied der Helmholtz-Gemeinschaft TSU TBILISI STATE UNIVERSITY The pn-system Study at Internal ANKE Experiment

Mitglied der Helmholtz-Gemeinschaft TSU TBILISI STATE UNIVERSITY The pn-system Study at Internal ANKE Experiment David Mchedlishvili HEPI, Tbilisi State University IKP, Forschungszentrum Jülich GGSWBS’ 12

Outline: o Motivation o dp→(pp)sn reaction o Experimental setup • Single polarised • Double

Outline: o Motivation o dp→(pp)sn reaction o Experimental setup • Single polarised • Double polarised o Results • Cross section • Tensor analysing powers • Spin correlation parameters • First results on ∆ channel o Overview of the future experiment o Summary and outlook August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

np Scattering data § Current experimental status of np data § ANKE is able

np Scattering data § Current experimental status of np data § ANKE is able to improve np database by providing a precise data at up to 2. 9 Ge. V/A np charge-exchange d /d np charge-exchange Ayy ANKE range np forward August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

np charge-exchange (large angles) →→ n dp→(pp)1 S n 0 → d D At

np charge-exchange (large angles) →→ n dp→(pp)1 S n 0 → d D At small excitation energies in the final pp system 1 S 0 state → ↑n p ↑p Spin-flip from 3 S 1, 3 D 1 of the deuteron to 1 S 0 of the diproton. Data sensitive to spin-flip, isospin-flip transitions. ↑psp ↓p 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. A 467 (1987) 575 August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Proof of principle at 1. 17 Ge. V Results: • Method works at Tn

Proof of principle at 1. 17 Ge. V Results: • Method works at Tn = 585 Me. V • Application to higher energies Td=1. 6, 1. 8, 2. 27 Ge. V D. Chiladze et al. PLB 637, 170 (2006) D. Chiladze et al. EPJA, 40, 23 (2009) Tn = 585 Me. V SAID np amplitudes August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Experimental setup Single polarised: • • • Beam: Polarised deuterons at Td=1. 2, 1.

Experimental setup Single polarised: • • • Beam: Polarised deuterons at Td=1. 2, 1. 6, 1. 8, 2. 27 Ge. V Target: Unpolarised hydrogen cluster target Objectives: dσ/dq, Axx, Ayy Double polarised: • • • Beam: Polarised deuterons at Td=1. 2, 2. 27 Ge. V Target: Polarised ABS cell target Objectives: Ayp, Cx, x, Cy, y Higher Energy 1. 2 Ge. V t August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Polarised internal gas target at ANKE • • • Atomic Beam Source (ABS) provided

Polarised internal gas target at ANKE • • • Atomic Beam Source (ABS) provided polarised H gas in the cell § Qy = 0, -1, +1. § Density ≈ 1013 cm-2 Cell: 20 x 15 x 370 mm 3 Lamb-shift Polarimetry Complications due to cell: • Dedicated beam development involving stacking injections and electron cooling • Background handling August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Reaction identification at 1. 2 Ge. V dp→(pp)n and np→dπ0 reactions provide double track

Reaction identification at 1. 2 Ge. V dp→(pp)n and np→dπ0 reactions provide double track events in forward detector: • pp from dp→(pp)n ∆tmeas [ns] • dpsp from quasi-free np→dπ0 Fast pp pairs are distinguished from dpsp using time of flight method ∆ttof [ns] August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Beam polarimetry Beam polarisation is measured at Td = 1. 2 Ge. V and

Beam polarimetry Beam polarisation is measured at Td = 1. 2 Ge. V and “polarisation export” technique is applied to higher energies → • np→dπ0 Pz (SAID Ay for pp→dπ+) • dp→(pp)sn Pzz (Axx, Ayy from previous ANKE measurements) → → Normalised count ratio of dp→(pp)sn events for low excited pp pairs (Epp< 3 Me. V): → Normalised count ratio of np→dπ0 events: Pz up to 70% Pzz up to 80% August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Single polarised data: dσ/dq, Axx, Ayy Td = 1. 6 Ge. V Td =

Single polarised data: dσ/dq, Axx, Ayy Td = 1. 6 Ge. V Td = 1. 8 Ge. V Td = 2. 27 Ge. V Large discrepancy August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Double polarised data →→ • dp→(pp)1 S 0 n • Epp < 3 Me.

Double polarised data →→ • dp→(pp)1 S 0 n • Epp < 3 Me. V August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Double polarised data: Ayp →→ • dp→(pp)1 S 0 n Td = 1. 2

Double polarised data: Ayp →→ • dp→(pp)1 S 0 n Td = 1. 2 Ge. V • Epp < 3 Me. V • With beam state Pz = 0; Pzz = 0. Td = 2. 27 Ge. V August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Double polarised data: Cy, y Cx, x →→ • dp→(pp)1 S 0 n Td

Double polarised data: Cy, y Cx, x →→ • dp→(pp)1 S 0 n Td = 1. 2 Ge. V • Epp < 3 Me. V • With beam state Pzz = 0; (Apy, Ady = 0) Td = 2. 27 Ge. V August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

dp→(pp)s∆0 reaction • • Td=1. 2 Ge. V Td=2. 27 Ge. V Epp<3 Me.

dp→(pp)s∆0 reaction • • Td=1. 2 Ge. V Td=2. 27 Ge. V Epp<3 Me. V Td = 1. 6 Ge. V dp→(pp)n dp→(pp)∆0 + ? ? ? Td = 1. 8 Ge. V Main mechanism: One pion exchange Td = 2. 27 Ge. V Valuable information on the modelling of the np→p∆0 amplitudes August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Tensor analysing powers dp→(pp)s∆0 High mass region: 1. 19 < MX < 1. 35

Tensor analysing powers dp→(pp)s∆0 High mass region: 1. 19 < MX < 1. 35 Ge. V/c 2 → dp→(pp)sn at Td = 1. 2 Ge. V Td = 1. 6 Ge. V COMPARE! Differences: Td = 1. 8 Ge. V Ø Signs are flipped Ø Axx and Ayy are small at qt=0 Td = 2. 27 Ge. V Valuable constraints on the modeling of the np→p∆0 amplitudes August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Future experiments Measurement of nucleon-nucleon elastic scattering at small angles up to the maximum

Future experiments Measurement of nucleon-nucleon elastic scattering at small angles up to the maximum COSY energy Byproducts: • pd→(pp)sn: two slow protons detected in the STT • pd→pd: the deuteron is detected in an STT (small angles) or in ANKE (large angles) • pd→(pp)s∆0 : two protons detected in the STT and ∆0 decay products possibly detected in ANKE • pd→pspd. X (quasi free pn→d. X): fast deuteron detected in ANKE • pd→psp{pp}s π‾ : two fast protons detected in ANKE • pd→ 3 He π0 : the 3 He is detected in ANKE August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12

Summary ü dp→(pp)sn observables: 1. dσ/dq, Axx, Ayy at Td = 1. 2, 1.

Summary ü dp→(pp)sn observables: 1. dσ/dq, Axx, Ayy at Td = 1. 2, 1. 6, 1. 8, 2. 27 Ge. V 2. Ayp, Cx, x, Cy, y at Td = 1. 2, 2. 27 Ge. V THANK YOU ü dp→(pp)s∆0 observables: dσ/dm, Axx, Ayy at Td = 1. 6, 1. 8, 2. 27 Ge. V Outlook Ø Further investigation of the dp→(pp)s∆0 reaction by using double polarised data Ø Extension of the np program at ANKE by using proton beams at COSY August 6, 2012 The pn-system Study at Internal ANKE Experiment GGSWBS’ 12