1 / 39

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.

gala
Télécharger la présentation

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

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related