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19-23 April 2010 DIS 2010 / Florence Neutron Single Target Spin Asymmetries in SIDIS

19-23 April 2010 DIS 2010 / Florence Neutron Single Target Spin Asymmetries in SIDIS (at JLab HallA) E. Cisbani INFN Rome and Italian National Institute of Health on behalf of the 6 GeV Transversity collaboration http://hallaweb.jlab.org/experiment/transversity/. Outline.

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19-23 April 2010 DIS 2010 / Florence Neutron Single Target Spin Asymmetries in SIDIS

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  1. 19-23 April 2010 DIS 2010 / Florence Neutron Single Target Spin Asymmetries in SIDIS (at JLab HallA) E. Cisbani INFN Rome and Italian National Institute of Health on behalf of the 6 GeV Transversity collaboration http://hallaweb.jlab.org/experiment/transversity/ E. Cisbani: n SSA @ JLab/Hall A

  2. Outline • Single Spin Asymmetries in SIDIS • Transversity Experiment in HallA • Kinematic • Target • Detectors (HRS + BB) • Hadrons Production • JLab 12 GeV prospective • SBS + SIDIS Experiment • SoLID-Transversity Experiment Experiment based on the excellent work of several PhD Students: C. Dutta (Kentucky), J. Huang (MIT), A. Kalyan (Kentucky), J. Katich (W&M), X. Qian (Duke), Y. Wang (UIUC), Y. Zhang (Lanzhou U) E. Cisbani: n SSA @ JLab/Hall A

  3. Nucleon Structure (at leading twist) quark L U T U nucleon L T E. Cisbani: n SSA @ JLab/Hall A

  4. Method: from SIDIS to SSA to DFFF Pretzelosity E. Cisbani: n SSA @ JLab/Hall A

  5. Collins Moments on proton/deuteron COMPASS/deuteron proton Hepex-0802.2160 From Pappalardo / Transversity 2008 • Proton: • K- and p- with opposite sign, strong flavor dependence (but K errors significant)! • K+ and p+ consistent with u dominance • COMPASS compatible with HERMES • Deuteron: consistent with 0, expected asymmetry on neutron as large as on proton From DIS2009 Larger effects at larger x E. Cisbani: n SSA @ JLab/Hall A

  6. Sivers Moments on proton/deuteron HERMES on p NEW DATA FROM COMPASS/Proton SEE H. Fischer talk in this conference COMPASS/deuteron PLB673(2009)127 PRL103(2009)152002 • Proton: • K+ twice p+ conflict with u dominance expectation • K- and p- consistent with 0 • COMPASS proton not fully compatible to HERMES • Deuteron: consistent with 0, expected asymmetry on neutron as large as on proton E. Cisbani: n SSA @ JLab/Hall A

  7. Extraction of DF and FF from a Global Fit Transversity first moment (assume DTsea = 0) HERMES/p + COMPASS/d (Q2~2.5 GeV2) e+e- from BELLE (Q2=110 GeV2) Sivers function Anselmino et al 12/08 Anselmino et al 05/08 Collins Fragmentation Function Collins: Unfav/Fav FF puzzle (not seen in Unpol FF) Sivers: large s-bar sea small E. Cisbani: n SSA @ JLab/Hall A

  8. JLab Accelerator Facility 6 GeV CEBAF (< 2013) Max Current: 200 mA Max Energy: 0.8 - 5.9 GeV Long. Polarization: 85% E. Cisbani: n SSA @ JLab/Hall A

  9. Transversity on neutron: Hall A experimental setup e+3He→e’+p(K)+X • Beam e-: • 5.9 GeV, 15 mA • Neutron Target: • High pressure polarized 3Hepol. 65%, 50 mg/cm2 x 40 cm • Luminosity: 1036/s/cm2 • Electron Arm (BigBite): • E’=0.72.2 GeV,J=30°, DW=64 msr • Hadron Arm (HRS Left): • Ph =2.35 GeV/c ± 5%,J=30°, DW=6 msr, p/K ID • Kinematic region: • Q2 ~ 2.2 GeV2,x ~ 0.130.45, z~ 0.5 • Measure Collins, Sivers and Pretzelosity E06-010 Data Taking:Nov/08 – Feb/09 E. Cisbani: n SSA @ JLab/Hall A

  10. 3He (n) Polarized Target • Polarized 3He ~ polarized neutron target • Use 3 COMET lasers (narrow line, high power) for optical pumping of Rb vapor • Fast spin exchange (via K) by 3He hyperfine interaction in oven; small part of N2 to quench soft photon depolarization of Rb • Polarized 3He diffuses to the target chamber • Transverse Horizontal (In-plane) and Vertical orientations • 20 minute spin flip • NMR and EPR polarimetries • Superior performances: • Steady 65% polarization @ 15 uA beam (world record) E. Cisbani: n SSA @ JLab/Hall A

  11. Electron Arm (BigBite) E. Cisbani: n SSA @ JLab/Hall A

  12. Hadron Arm: HRS-L 1.27 E. Cisbani: n SSA @ JLab/Hall A

  13. Measured Phase Space Q2>1, W>2.3, Mm>1.6, 0.3<z<0.7 E. Cisbani: n SSA @ JLab/Hall A

  14. Hadron Identification • Aerogel Cherenkov Counter • p rejection > 98% • Time of Flight • K/p separation at 4s • RICH proximity focusing detector • K/p separation at 3.8s Preliminary Ph = 2.33 – 2.47 GeV/c E. Cisbani: n SSA @ JLab/Hall A data from APS2010 / Y. Wang

  15. Projected Stat. on p Asymmetries Work in progress on systematics evaluation Preliminary results expected to be released within summer/2010 ! E. Cisbani: n SSA @ JLab/Hall A

  16. JLab at 12 GeV and the TMD measurements prospective in Hall A E. Cisbani: n SSA @ JLab/Hall A

  17. add Hall D (and beam line) Upgrade magnets and power supplies CHL-2 CEBAF 12 GeV upgrade 6 GeV CEBAF (< 2013) Max Current: 200 mA Max Energy: 0.8 - 5.9 GeV Long. Polarization: 85% 12 GeV CEBAF (>2014) 310 MUSD Max Current: 90 mA Max Energy Hall A,B,C: 10.9 GeV Max Energy Hall D: 12 GeV Long. Polarization: 75-85% E. Cisbani: n SSA @ JLab/Hall A

  18. Peculiarity of JLab Phase Space Access unexplored valence region (high Q2 requires high luminosity) Hall A is already running at 1036 and will likely reach few 1038 (in polarized experiments) E. Cisbani: n SSA @ JLab/Hall A from TMD-Duke / M. Contalbrigo

  19. SSA on n in the 11 GeV era in Hall A Measure Transversity / Sivers / Pretzelosity and more • SIDIS on p and K (conditionally approved, 01/2009) – short term • G. Cates, E. Cisbani, G.B. Franklin, B. Wojtsekhowski • Similar layout of the 6GeV experiment at higher luminosity and acceptance • HRS replaced by a new large acceptance spectrometer (SBS), improved target • 2D binning on the relevant variables: x, P and z, for both hadrons and Q2 dependence • High x valence region (with overlap to HERMES, COMPASS, JLab6 data) • Proposal: http://hallaweb.jlab.org/collab/PAC/PAC34/PR-09-018-sidis.pdf • SoLID-Transversity experiment (approved, 01/2010) – medium term • J.-P. Chen, H. Gao, X. Jiang, J.-C. Peng, and X. Qian • 2p angular coverage • Use solenoid magnet • Precision measurement in 4D phase space (x, z, P and Q2) • Better systematic control due to the 2p geometry • Extended phase space coverage • Proposal: http://hallaweb.jlab.org/collab/PAC/PAC35/PR-10-006-SoLID-Transversity.pdf E. Cisbani: n SSA @ JLab/Hall A

  20. HERMES RICH SIDIS: Experimental Setup e+3He→e’+p(K)+X Measure the SSA of SIDIS processes n(e,e’p)X and n(e,e’K)X BB: e-arm at 30o  = 45 msr GEM Tracker Gas Cherenkov Shower  GMn/PR-09-019 SBS: h-arm at 14o  = 50 msr GEM tracker excellent PID / RICH Hadron CALO Event rate: ~104×HERMES 60 days of production expected stat. accuracy: 1/10 of proton HERMES Beam: 50 A, E=8.8 and 11 GeV (80% long. Pol.) Target: 65% polarized 3He  GEn(2)/PR-09-016  Luminosity: 1.4×1037 cm-2s-1, 0.05 sr PAC34 Conditionally Approved experiment E. Cisbani: n SSA @ JLab/Hall A

  21. SIDIS: A new target E. Cisbani: n SSA @ JLab/Hall A from SBS-IV / G.D. Cates

  22. SIDIS: Hadron PID HERMES RICH 5.5 GeV K+ C4F10 gas REAL DATA from NIMA 479 (2002) 511 14.6 GeV e- 1.5 GeV p- Very stable performance (dn/(naerogel-1)= 1%, 9 years) Stored at UVa under safe/controlled conditions (also additional wall of spare Aerogel) E. Cisbani: n SSA @ JLab/Hall A

  23. Prop. Exp. Ebeam = 11.0 GeV Prop. Exp. Ebeam = 8.8 GeV Current Transversity Exp. E06-010 SIDIS: Q2 coverage We will investigate the Q2 dependence of the Sivers and Collins functions, with overlap in the region of HERMES; reveal higher twist effects. Analysis of the Q2 effect will use also the results of 6 GeV E06-010 Transversity experiment E. Cisbani: n SSA @ JLab/Hall A

  24. SIDIS: Expected Statistical Accuracy on K • Superior quality of Kaon data • Extend at higher x with partial overlap with existing data on proton, deuteron and expected results of HallA Transversity 6 GeV DF from CTEQ5M FF from DSS Rate normalized to HERMES/p+d K production E. Cisbani: n SSA @ JLab/Hall A

  25. SoLID: experimental setup E10-006 PAC35 Approved experiment E. Cisbani: n SSA @ JLab/Hall A from JLab-PAC35 / X. Qian

  26. SoLID: Phase Space E. Cisbani: n SSA @ JLab/Hall A from JLab-PAC35 / X. Qian

  27. x SoLID: Projected Data E. Cisbani: n SSA @ JLab/Hall A from JLab-PAC35 / X. Qian

  28. Summary • 6 GeV Transversity Experiment • Excellent data taking • Almost completed analysis • First results will be released soon (likely before Summer/2010) • 12 GeV Prospective • Two complementary experiments proposed on n-SSA SIDIS in HallA, • different time scale and performance; • both will benefit of JLab luminosity and 3He polarized targets. E. Cisbani: n SSA @ JLab/Hall A

  29. Backup Slides E. Cisbani: n SSA @ JLab/Hall A

  30. Polarized SI-DIS process E. Cisbani: n SSA @ JLab/Hall A

  31. SBS for SIDIS E. Cisbani: n SSA @ JLab/Hall A

  32. GEn(2)  High Lumi Target • 60% transverse polarization • Support 60 uA beam current • Extended target cell (60 cm) • Use proved alkali-hybrid mixture technique for polarization transfer • Improved diagnostics for optimal tuning of the potassium-rubidium ratio • Use line-narrowed high-power diode-laser arrays • Use convection for gas mixing between target and pumping chambers • Better description of the target behavior by the identification of the relaxation rate (X-term) • Use of metal target cell E. Cisbani: n SSA @ JLab/Hall A

  33. Systematics/Physics • Target FSI relative error: expected <7% following the analysis of Scopetta/Transversity/2008 • Higher Twists: • we will study the Q2 dependence with high statistics; • terms will be included into the fit whose stability benefits again of the high statistics • Unpolarized analysis will also be carried on E. Cisbani: n SSA @ JLab/Hall A

  34. Systematics/Exp. Apparatus • Random • dilution factor expected to be small < 1% (S/N = 67/0.3) • Relative error well below 10% • Vector Meson: • from PHYTIA prediction tuned on HERMES data below 2.5%; lower at higher x • can be studied at higher z • Acceptances: • azimuthal angles are well covered even with partial fh coverage • X,z,P,Q2 effects suppressed by 2D (at least) binning • Radiative QED Effects: • Influence x,Q2 and azimuthal angles; PHYTIA can be used to estimate the correction factor (and systematic error) • According to HERMES we expect a systematic error <5% • PID: • RICH detector with up to 5% occupancy expect to provide 4s separation at least E. Cisbani: n SSA @ JLab/Hall A

  35. Figure of Merit Two beam energy runs for Q2 dependence studies: E. Cisbani: n SSA @ JLab/Hall A

  36. Measure the SSA of SIDIS processes n(e,e’p)X and n(e,e’K)X • Extract Sivers and Collins (and Pretzelosity) asymmetries on p and K with high statistics • Provide 2D binning (at least) on the relevant variables: x, P and z, for both hadrons • Provide Q2 dependence • Explore for the first time the high x valence region (with overlap to HERMES, COMPASS, JLab6 data) • Understanding of QCD dynamics in the nucleon by the Sivers effect • Improve knowledge of the nucleon structure in terms of parton distribution functions • Shed more light on the origin of the nucleon spin E. Cisbani: n SSA @ JLab/Hall A

  37. SIDIS 12GeV: What is special • High Luminosity: • 105 larger than in HERMES • High target polarization (65%) • Fast target polarization switch (120 seconds) • 4 (8) transverse polarization directions • Use of SBS (and BB): • Large solid angle (50 msr), very good angular and vertex resolutions • Large momentum coverage (2-7 GeV/c) • Excellent hadron PID • Reuse equipment from GEp(5) (approved), GEn(2) and GMn (proposals) E. Cisbani: n SSA @ JLab/Hall A

  38. Expected Statistical Accuracy on p Contalbrigo/SPIN08 5×5 bins (0.15<x<0.65, 0.2<z<0.7) (only one shown) High x region, with partial overlap with HERMES 2D binning in (x,z), (x,P) and (z,P) for p and K and Q2 dependence DF from CTEQ5M FF from DSS E. Cisbani: n SSA @ JLab/Hall A

  39. RICH stability in Trans 09 E. Cisbani: n SSA @ JLab/Hall A

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