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June 25, 2012 | ANKE/PAX SPIN Physics Workshop

The ANKE Experiments at COSY: physics program and technical development (including future plans) Andro Kacharava (IKP, FZ Jülich). June 25, 2012 | ANKE/PAX SPIN Physics Workshop. Outline. Introduction Current status of program: Experiments using polarized beams and/or targets

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June 25, 2012 | ANKE/PAX SPIN Physics Workshop

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  1. The ANKE Experiments at COSY:physics program and technical development (including future plans)Andro Kacharava (IKP, FZ Jülich) June 25, 2012 | ANKE/PAX SPIN Physics Workshop

  2. Outline • Introduction • Current status of program: • Experiments using polarized beams and/or targets • NN scattering program • Selected results (pp/pn) • Near future: • Double-polarized measurements for NN program • Towards longitudinally polarized beams – pion program • Time line • Beyond 2014 ANKE Experiments at COSY

  3. Introduction – COSY Facilities • Hadron physics with hadronic probes • Experimental set-ups: • ANKE • WASA • EDM • (BNL/JEDI) • PAX • TOF (ext.) WASA ANKE EDM PAX TOF … the machine for hadron spin physics Andro Kacharava ANKE Experiments at COSY 3

  4. ANKE/COSY – Advantages of Internal Exp.‘s Feature/ Technique  „Good for“ (examples) • Precision / Schottky Luminosity (target density) • Spin manipulation / RF  Precise momentum determination, • dipole, solenoid systematics • Cooling / e-cooler,  Beam quality • stochastic • Low momentum recoils  On-line polarimetry, • Spectator detection effective neutron-target • Thin targets  Signal-to-background ratio • Gas jet, very thin foils • Dense targets  Small x-section measurements • Cluster, pellet • Large acceptance (near th.) Calibration of spectrometer • 2-body kinematics • ....

  5. COSY: Tools at ANKE ANKE PIT → STT ANKE Experiments at COSY

  6. Technical developments: PIT/STT • Openable cell (target density) • 4 STT modules • Snake concept ANKE Experiments at COSY

  7. Technical developments: PIT status Polarized deuterium (ABS) target: test measurements at ANKE using the Lamb-Shift polarimeter (recent results - May 2012) ANKE Experiments at COSY

  8. Technical developments: Snake concept • Should allow for flexible use at two locations • Fast ramping (< 30s) • Cryogen-free system ANKE ANKE PAX PAX ANKE Experiments at COSY

  9. Physics program: Overview 1. NN scattering ↔ Nuclear forces 2. Meson production ↔ ChPT, phenomenological models, FSI 3. Hyperon production ↔ SU(3) symmetry See talks: “Pion program” – S. Dymov “Eta-meson” – M. Papenbrock “Hyperon production” – Yu. Valdau “Kaon-pair production” – A. Dzyuba Since 2005 ANKE has been equipped with a Polarized Internal Target (PIT) and embarked to measure the SPIN dependence of many polarized reactions: New insight into the strong interaction physics at intermediate energies ! ► Described in ANKESPIN document: COSY proposal #152, “Spin Physics from COSY to FAIR” (nucl-ex/0511028) ANKE Experiments at COSY

  10. Physics program: Present status • Performing single and double polarization experiments; • 2 weeks run conducted last week (June 2012) on: • ►“Initial research with polarized deuterium target” (exp.201) • Preparing approved (un)polarized measurements (PAC #40): • ►“NN elastic scattering up to maximum COSY energy” (exp. 212) • ► “Measurement of quasi-free pn→dη reaction” (exp.211) • ►“Initial research with longitudinal polarized proton beam” (exp.213) • Data analysis of previous (un)polarized experiments ! ANKE Experiments at COSY

  11. NN program: pp elastic d/d (pp) • Description of nucleon-nucleon interaction requires precise data for Phase Shift Analysis • COSY-EDDA collaboration produced wealth of data forpp elastic scattering. • There are no experimental data at low angles (θcm<30°)above 1.0 GeV energy. Ay (pp) EDDA ANKE ANKE Experiments at COSY

  12. NN program: np system np charge-exchange • R. Arndt: “Gross misconception within the community that np amplitudes are known up to a couple of GeV. np data above 800 MeV is a DESERT for experimentalists.” d/d (np) ANKE np charge-exchange np forward Ayy (np) ANKE is able to provide the experimental data both for pp and np systems and improve our understanding of NN interaction ANKE np forward ANKE Experiments at COSY

  13. COSY: Polarization observables in npscattering Experimental program: NN interaction Unpolarised intensity depends only upon spin-flip amplitudes: Terms can be separated by measuring with polarised 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.Wilkin., Nucl.Phys.A467 (1987) 575 ANKE Experiments at COSY

  14. → np study: Proof of principle dp→{pp}1S0n • To check the feasibility of the program first experimental data was taken with deuterium beam at Tn = 600 MeV to compare with tested theoretical predictions: D.V.Bugg & C.Wilkin., Nucl.Phys.A467 (1987) 575 D. Chiladze et al., PRST-AB 9, 050101 (2006) D. Chiladze et al., PLB 637, 170 (2006) D. Chiladze et al., EPJ. A 40 (2009) → → dp→(pp)n Tn = 600 MeV dp→(pp)n Tn = 600 MeV ANKE Experiments at COSY

  15. Status of np program: Analysing powers → dp→{pp}1S0n Tn = 800 MeV Tn= 1150 MeV Preliminary Results differ from theory at Tn=1150 MeV, especially for low transferred momentum region Tn = 900 MeV D. Mchedlishvili et al., JP-CS, 295, 012099 (2011) ANKE Experiments at COSY

  16. → Status of np program: Spin correlations → dp→(pp)1S0n Relative phases between the amplitudes Tn = 1150 MeV Tn = 600 MeV Cy,y Cy,y Preliminary Cx,x Cx,x ANKE Experiments at COSY

  17. Status of np program: dp → {pp}Δ0 Tn = 800 MeV dσ/dm Tn = 800 MeV Tn = 900 MeV Tn = 900 MeV Preliminary dσ/dm Tn = 1150 MeV Tn = 1150 MeV dσ/dm D. Mchedlishvili et al., JP-CS, 295, 012099 (2011) ANKE Experiments at COSY

  18. Status of pp program: Frequency shift Exp. #200 T0 = 1.0 GeV (η>0) • Beam-target interaction gives energy loss that changes the machine frequency. • Frequency change depends on η parameter • Schottky distribution was recorded in every 10 sec. throughout the 300 sec. cycle. T0 = 2.0 GeV (η<0) Meanfrequency 10 sec. 80 sec. Cycle time 150 sec. Spectral Density of Schottky Power [arb. units] 220 sec. 290 sec. 1429.45 1429.50 1429.55 1548.10 1548.20 1548.30 Revolution Frequency [kHz] Revolution Frequency [kHz] ANKE Experiments at COSY

  19. Status of pp program: Luminosity Exp. #200 1 2 3 4 1 2 3 4 With 2-3 % accuracy ANKE Experiments at COSY

  20. Status of pp program: Cross section Exp. #200 • Only FD system is used. • Reconstructed missing mass of the proton ≈ 938 ± 18 MeV. Tp = 1.0 GeV 13 - 14° 20 - 21° 27 - 28° Preliminary SAID SAID SAID  ANKE  ANKE  ANKE Tp = 2.8 GeV Tp = 2.0 GeV ANKE Experiments at COSY

  21. Near future: Two examples Next PAC meeting (#41) • Double-polarized measurements for NN sector (Exp.“212.1“) requirements: pol. beam, pol. target (D), 4 STT‘s, openable cell, roughly ~ 7-8 weeks of BT • Axz measurement for pion production (Exp. “213.1“) requirements: + Snake@PAX, roughly ~ 10 weeks of BT • Synergy (and coordination) with PAX and TRIC Exp.‘s ! ANKE Experiments at COSY

  22. Time line: up to 2014 ↓___↓____________________↓__ 2012 PAC#40 Exp. 201 Snake delivery ____↓____I ANKE BTI___ ↓ __________________↓________ 2013 SnakeExp.s: 211, 212 PAC#41 Double-pol. (Exp. 212.1) @PAX ____↓_____________↓_____________↓__________↓_ 2014 Exp. 213.1 (Axz) PAC#42 Double-pol. (Exp.#???) Snake@ANKE ANKE Experiments at COSY

  23. Time line: beyond 2014 Examples (PAC #42): • Explore longitudinal polarized beam for spin observables in NN sector • Develop concept and start to create polarimetry data base for the COSY EDM project via measurement of spin dependence of the pp, pd and dp elastic processes • Strangeness production – (Λn) scattering length: singlet (as) and triplet (at) part separately via spin correlation parameter (Cyy) measurements (► depends on TOF result on Λp system) ANKE Experiments at COSY

  24. The END • Many thanks to the workshop organizers !

  25. The END

  26. Spare transparencies ANKE Experiments at COSY

  27. Strangeness production: YN Interaction ΛNscatteringlength: singlet (as) andtriplet (at) partseparately • Poor data base: • - LN little known • - SN nothing known • YN scattering experiments difficult •  large uncertainty in Lp scattering length • Theory • Model-freedetermination in productionreactions • Method:dispersionrelations • Theoryprecisionis 0.3 fm • Spin/isospin dependence • TOF:high-resolutionsinglepolarized • p+p→K+(Λp)at(θK,cm = 90°) at • ANKE:double polarized p+n→K+(Λn) • (1 – CNN)·σ at (θK,cm= 0°)  as →  → → A. Gasparyan et al., PRC 69, 034006 (2004) ANKE Experiments at COSY

  28. 2005-2009 2010-2014 COSY proposal #152 ArXiv:nucl-ex/0511028

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