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) Worm-gear II Asymmetries on pi+/pi- (published) New Preliminary SSA Results from JLab Hall A with a Transversely polarized 3 He (n) Collins/Sivers Asymmetries in K+/K- Pretzelosity Asymmetries on +/ - 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 3 He and p Acknowledgement: thanks to J.P Chen and Jefferson lab Transversity collaboration for some slides
Unpolarized Structure Function F 2 Bjorken Scaling Scaling Violation Gluon radiation – QCD evolution NLO: Next-to-Leading-Order One of the best experimental tests of QCD
Parton Distribution Functions (CTEQ6) JHEP 1001: 109 (2010)
Polarized Structure functions
Polarized Parton Distributions DSSV, PRL101, (2008)
3-D Structure Generalized Parton Distributions Transverse Momentum-Dependent Distributions The next Frontier
TMDs 2+1 D picture in momentum space Bacchetta, Conti, Radici GPDs 2+1 D picture in impact-parameter space QCDSF collaboration Towards Imaging - Two Approaches intrinsic transverse motion spin-orbit correlations- relate to OAM non-trivial factorization accessible in SIDIS (and Drell-Yan) collinear but long. momentum transfer indicator of OAM; access to Ji’s total J q,g existing factorization proofs DVCS, exclusive vector-meson production
Transverse Spin: Transversity Three twist-2 quark distributions: Momentum distributions: q(x,Q 2 ) = q ↑ (x) + q ↓ (x) Longitudinal spin distributions: Δq(x,Q 2 ) = q ↑ (x) - q ↓ (x) Transversity distributions: δq(x,Q 2 ) = 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 P T ) Distribution functions depends on x, k ┴ and Q 2 : δq, f 1T ┴ (x, k ┴,Q 2 ), … Fragmentation functions depends on z, p ┴ and Q 2 : D, H 1 (x,p ┴,Q 2 ) Measured asymmetries depends on x, z, P ┴ and Q 2 : Collins, Sivers, … (k ┴, p ┴ and P ┴ are related)
Leading-Twist TMD PDFs f 1 = f 1T = Sivers Helicity g 1 = h1 =h1 = Transversity h1 =h1 =Boer-Mulders h 1T = Pretzelosity g 1T = Worm Gear h 1L = Worm Gear : Probed with transversely pol target HERMES, COMPASS, JLab E Nucleon Spin Quark Spin
Separation of Collins, Sivers and pretzelocity effects through angular dependence
Operated by the Southeastern Universities Research Association for the U.S. Department of Energy Thomas Jefferson National Accelerator Facility COMPASS Sivers asymmetry 2010 data x > region - comparison with HERMES results
E06 ‑ 010 Experiment Spokespersons: Chen/Evaristo/Gao/Jiang/Peng First measurement on n ( 3 He) Polarized 3 He Target Polarized Electron Beam, 5.9 GeV BigBite at 30º as Electron Arm – P e = 0.7 ~ 2.2 GeV/c HRS L at 16º as Hadron Arm – P h = 2.35 GeV/c – Excellent PID for /K/p 7 PhD Thesis Students (All graduated) + new students 12 Beam Polarimetry (Møller + Compton) Luminosity Monitor
Published Results (I) from JLab Hall A E with a Transversely Polarized 3 He (n) Collins/Sivers Asymmetries on +/ - X. Qian at al., PRL 107:072003(2011)
E He Target Single-Spin Asymmetry in SIDIS 3 He Sivers SSA: negative for π +, 3 He Collins SSA small Non-zero at highest x for + Blue band: model (fitting) uncertainties Red band: other systematic uncertainties
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
Published Results (II) from JLab Hall A E with a Transversely Polarized 3 He (n) Worm-Gear II: Trans-helicity on +/ - J. Huang et al., PRL. 108, (2012).
Asymmetry A LT Result 3 He A LT : Positive for - To leading twist:
–Corrected for proton dilution, f p –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 Neutron A LT Extraction Trans-helicity
Preliminary New Results (I) from JLab Hall A E with a Transversely Polarized 3 He (n) Collins/Sivers Asymmetries on K+/K- Analysis by Y. Zhao (USTC), Y. Wang (UIUC)
Kaon PID by Coincidence time of flight Cross checked with RICH results K+/π+ ratio: ~5% K-/π- ratio: ~1%
Preliminary K+/K- Collins and Sivers Asymmetries on 3 He
Preliminary New Results (II) from JLab Hall A E with a Transversely Polarized 3 He (n) Pretzelosity on +/ - Analysis by Y. Zhang (Lanzhou) and X. Qian (Caltech)
Pretzelosity on +/ - Preliminary
Extracted Results on Neutron
Preliminary New Results (III)from JLab Hall A E with a polarized 3 He (n) Inclusive Electron SSA Analysis by J. Katech(W&M), X. Qian (Caltech)
Inclusive Target Single Spin Asymmetry: DIS 3 He θ e-e- Unpolarized e - beam incident on 3 He target polarized normal to the electron scattering plane. However, A y =0 at Born level, sensitive to physics at order α 2 ; two-photon exchange. In DIS case: related to integral of Sivers Physics Importance discussed in A. Metz and M. Schlegel’s talks (Tuesday)
Inclusive Target Single-Spin Asymmetry Extracted neutron SSA Vertically polarized target
Future: TMD study with SoLID at 12 GeV JLab Hall A Precision 4-D mapping of Collins/Sivers/Pretzelosity Worm-Gear I/II with Polarized 3 He (Neutron) and Proton
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 ┴,Q 2 ) Multi-facilities, global effort Precision high statistics high luminosity and large acceptance
SoLID for SIDIS/PVDIS with 12 GeV JLab 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
E /E , Both Approved with “A” Rating Mapping of Collins(Sivers) Asymmetries with SoLID Both + and - Precision Map in region x( ) z( ) Q 2 (1-8) P T (0-1.6) <10% d quark tensor charge Collins Asymmetry
Map Collins and Sivers asymmetries in 4-D (x, z, Q 2, P T )
Expected Improvement: Sivers Function Significant Improvement in the valence quark (high-x) region Illustrated in a model fit (from A. Prokudin) f 1T =
E : Worm-gear functions (“A’ rating: ) Spokespersons: Chen/Huang/Qiang/Yan Dominated by real part of interference between L=0 (S) and L=1 (P) states No GPD correspondence Lattice QCD -> Dipole Shift in mom. space. Model Calculations -> h 1L =? -g 1T. h 1L = g 1T = Longi-transversity Trans-helicity Center of points:
Future: TMD study with SoLID at 12 GeV JLab Hall A New Letter Of Intent: Dihadron Production
Measure Transversity via Dihadron with SoLID LoI submitted to Jlab PAC 40, J. Zhang, A. Courtoy, et al. Wide x b and Q 2 coverages Projected Statistics error for one (M ,z ) bin, integrated over all y and Q 2. Precision dihadron ( +/ -) production on a transversely polarized 3 He (n) Extract transversity on neutron Provide crucial inputs for flavor separation of transversity
Projected Statistics Error Hall A, SoLID program Polarized 3 He target, (~60% polarization) Lumi=10 36 (n)/s/cm 2 Wide x b and Q 2 coverages Bin central values labeld on axises 4-d (x b, Q 2, Z + -,M + - ) mapping Z scale (color) represent stat. error
Summary SSA and TMD study have been exciting and fruitful Recent and Preliminary Results from JLab Hall A with a transversely polarized 3 He (n) target Collins/Sivers asymmetries for +/ -/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