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Nilanga Liyanage , University of Virginia

New results on Neutron Single Target Spin Asymmetries from Transversely polarized 3 He target at Jlab. Nilanga Liyanage , University of Virginia. Recent SSA Results from JLab Hall A with a Transversely Polarized 3 He (n) Collins/ Sivers Asymmetries on pi+/pi- (published)

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Nilanga Liyanage , University of Virginia

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  1. New results on Neutron Single Target Spin Asymmetries from Transversely polarized 3He target at Jlab Nilanga Liyanage , University of Virginia • Recent SSA Results from JLab Hall A with a Transversely Polarized 3He (n) • Collins/Sivers Asymmetries on pi+/pi- (published) • Worm-gear II Asymmetries on pi+/pi- (published) • New Preliminary SSA Results from JLab Hall A with a Transversely polarized 3He (n) • Collins/Sivers Asymmetries in K+/K- • PretzelosityAsymmetries on p+/p- • Inclusive hadron SSA • Inclusive electron SSA (DIS, QE) • TMD study at JLab 12 GeV in Hall A: • SoLID Program on SSA/TMDs: 3 Approved Experiments on 3He and p • Acknowledgement: thanks to J.P Chen and Jefferson lab Transversity collaboration for some slides

  2. Unpolarized Structure Function F2 • Bjorken Scaling • Scaling Violation • Gluon radiation – • QCD evolution NLO: Next-to-Leading-Order • One of the best experimental tests of QCD

  3. Parton Distribution Functions (CTEQ6) JHEP 1001: 109 (2010)

  4. Polarized Structure functions

  5. Polarized Parton Distributions DSSV, PRL101, 072001 (2008)

  6. The next Frontier 3-D Structure Generalized Parton Distributions Transverse Momentum-Dependent Distributions

  7. Towards Imaging - Two Approaches TMDs GPDs 2+1 D picture in momentum space 2+1 D picture in impact-parameter space Bacchetta, Conti, Radici QCDSF collaboration • collinear but long. momentum transfer • indicator of OAM; access to Ji’s total Jq,g • existing factorization proofs • DVCS, exclusive vector-meson production • intrinsic transverse motion • spin-orbit correlations- relate to OAM • non-trivial factorization • accessible in SIDIS (and Drell-Yan)

  8. Transverse Spin: Transversity • Three twist-2 quark distributions: • Momentum distributions: q(x,Q2) = q↑(x) + q↓(x) • Longitudinal spin distributions: Δq(x,Q2) = q↑(x) - q↓(x) • Transversity distributions: δq(x,Q2) = q┴(x) - q┬(x) • It takes two chiral-odd objects to measure transversity • Semi-inclusive DIS Chiral-odd distributions function(transversity) Chiral-odd fragmentation function(Collins function) • TMDs: (without integrating over PT) • Distribution functions depends on x, k┴ and Q2 : δq, f1T┴ (x,k┴,Q2), … • Fragmentation functions depends on z, p┴ and Q2 : D, H1(x,p┴,Q2) • Measured asymmetries depends on x, z, P┴ and Q2 : Collins, Sivers, … (k┴, p┴ and P┴ are related)

  9. Leading-Twist TMD PDFs Nucleon Spin Quark Spin h1= Boer-Mulders f1 = h1L= Worm Gear Helicity g1 = h1= Transversity f1T= g1T= h1T= Sivers Worm Gear Pretzelosity : Probed with transversely pol target HERMES, COMPASS, JLab E06-010

  10. Separation of Collins, Sivers and pretzelocity effects through angular dependence

  11. COMPASS Sivers asymmetry 2010 data x > 0.032 region - comparison with HERMES results

  12. E06‑010 ExperimentSpokespersons: Chen/Evaristo/Gao/Jiang/Peng Luminosity Monitor • First measurement on n (3He) • Polarized 3He Target • Polarized Electron Beam, 5.9 GeV • BigBite at 30º as Electron Arm • Pe = 0.7 ~ 2.2 GeV/c • HRSL at 16º as Hadron Arm • Ph = 2.35 GeV/c • Excellent PID for p/K/p • 7 PhD Thesis Students (All graduated) + new students Beam Polarimetry (Møller + Compton)

  13. Published Results (I) from JLab Hall A E06-010 with a Transversely Polarized 3He (n) • Collins/Sivers Asymmetries on p+/p- X. Qian at al., PRL 107:072003(2011)

  14. E06-010 3He Target Single-Spin Asymmetry in SIDIS 3He Collins SSA small Non-zero at highest x for p+ 3He Sivers SSA: negative for π+, Blue band: model (fitting) uncertainties Red band: other systematic uncertainties

  15. Results on Neutron Collins asymmetries are not large, except at x=0.34 Sivers negative Blue band: model (fitting) uncertainties Red band: other systematic uncertainties

  16. Published Results (II) from JLab Hall A E06-010 with a Transversely Polarized 3He (n) Worm-Gear II: Trans-helicity on p+/p- J. Huang et al., PRL. 108, 052001 (2012).

  17. Asymmetry ALT Result • 3He ALT : Positive for p- To leading twist:

  18. Neutron ALT Extraction • Corrected for proton dilution, fp • Predicted proton asymmetry contribution < 1.5% (π+), 0.6% (π-) • Dominated by L=0 (S) and L=1 (P) interference • Consist w/ model in signs, suggest larger asymmetry Trans-helicity

  19. Preliminary New Results (I) from JLab Hall A E06-010 with a Transversely Polarized 3He (n) Collins/Sivers Asymmetries on K+/K- Analysis by Y. Zhao (USTC), Y. Wang (UIUC)

  20. Kaon PID by Coincidence time of flightCross checked with RICH results K+/π+ ratio: ~5%K-/π- ratio: ~1%

  21. Preliminary K+/K- Collins and SiversAsymmetries on 3He

  22. Preliminary New Results (II) from JLab Hall A E06-010 with a Transversely Polarized 3He (n) Pretzelosity on p+/p- Analysis by Y. Zhang (Lanzhou) and X. Qian (Caltech)

  23. Pretzelosityon p+/p- Pretzelosity Asymmetries, 3He(e,e’) With a transversely polarized target For both p+ and p-, consistent with zero within uncertainties. Preliminary

  24. Extracted Results on Neutron Extracted Pretzelosity Asymmetries, For both p+ and p-, consistent with zero within uncertainties. Preliminary Results

  25. Preliminary New Results (III)from JLab Hall A E06-010 with a polarized 3He (n) Inclusive Electron SSA • Analysis by J. Katech(W&M), X. Qian (Caltech)

  26. Inclusive Target Single Spin Asymmetry: DIS θ 3He e- • Unpolarizede- beam incident on 3He target polarized normal to the • electron scattering plane. • However, Ay=0 at Born level, •  sensitive to physics at order α2; two-photon exchange. • In DIS case: related to integral of Sivers • Physics Importance discussed in A. Metz • and M. Schlegel’s talks (Tuesday)

  27. Inclusive Target Single-Spin Asymmetry Extracted neutron SSA Vertically polarized target

  28. Future: TMD study with SoLID at 12 GeVJLab Hall A Precision 4-D mapping of Collins/Sivers/Pretzelosity Worm-Gear I/II with Polarized 3He (Neutron) and Proton

  29. JLab 12 GeV Era: Precision Study of TMDs From exploration to precision study with 12 GeV JLab Transversity: fundamental PDFs, tensor charge TMDs: 3-d momentum structure of the nucleon  Quark orbital angular momentum Multi-dimensional mapping of TMDs 4-d (x,z,P┴,Q2) Multi-facilities, global effort Precision  high statistics high luminosity and large acceptance

  30. SoLID for SIDIS/PVDIS with 12 GeVJLab • Exciting physics program: • Five approved experiments: • three SIDIS “A rated”, one PVDIS “A rated”, one J/Psi “A- rated” • International collaboration: eight countries and 50+ institutions • CLEOII Magnet • GEMs for tracking • Cherenkov and EM Calorimeter for electron PID • Heavy Gas Cherenkov and MRPC (TOF) for pion PID

  31. E12-10-006/E12-11-108, Both Approved with “A” Rating Mapping of Collins(Sivers) Asymmetries with SoLID • Both p+ and p- • Precision Map in region x(0.05-0.65) z(0.3-0.7) Q2(1-8) PT(0-1.6) • <10% d quark tensor charge Collins Asymmetry

  32. Map Collins and Sivers asymmetries in 4-D (x, z, Q2, PT)

  33. Expected Improvement: Sivers Function f1T= • Significant Improvement in the valence quark (high-x) region • Illustrated in a model fit (from A. Prokudin)

  34. E12-11-107: Worm-gear functions (“A’ rating: ) Spokespersons: Chen/Huang/Qiang/Yan • Dominated by real part ofinterference between L=0 (S) and L=1 (P) states • No GPD correspondence • Lattice QCD -> Dipole Shift in mom. space. • Model Calculations -> h1L =? -g1T. h1L= Longi-transversity Trans-helicity Center of points: g1T=

  35. Future: TMD study with SoLID at 12 GeVJLab Hall A New Letter Of Intent: Dihadron Production

  36. Precision dihadron (p+/p-) production on a transversely polarized 3He (n) • Extract transversity on neutron • Provide crucial inputs for flavor separation of transversity Measure Transversity via Dihadron with SoLIDLoIsubmitted to Jlab PAC 40, J. Zhang, A. Courtoy, et al. Wide xb and Q2 coverages Projected Statistics error for one (Mpp,zpp) bin, integrated over all y and Q2.

  37. Projected Statistics Error • Hall A, SoLID program • Polarized 3He target, (~60% polarization) • Lumi=1036 (n)/s/cm2 • Wide xband Q2 coverages • Bin central values labeld on axises • 4-d (xb, Q2, Zp+p-,Mp+p-) mapping • Z scale (color) represent stat. error

  38. Summary • SSA and TMD study have been exciting and fruitful • Recent and Preliminary Results from JLab Hall A with a transversely polarized 3He (n) target Collins/Sivers asymmetries for p+/p-/K+/K- Pretzelosity on pi+/pi- SSA: inclusive hadron SSA: inclusive electron DIS SSA: inclusive electron (Quasi)Elastic • Planned SoLID program with JLab12 Precision 4-d mapping of TMD asymmetries

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