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Studies of Partonic Structure using SIDIS

Studies of Partonic Structure using SIDIS. H.Avakian (JLab). Hall-C collaboration meeting, JLab, Jan 22. Outline. Describe the complex nucleon structure in terms of partonic degrees of freedom of QCD. Transverse Momentum Distributions (TMDs) of quarks

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Studies of Partonic Structure using SIDIS

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  1. Studies of Partonic Structure using SIDIS H.Avakian (JLab) Hall-C collaboration meeting, JLab, Jan 22 JLab, Jan 2010

  2. Outline Describe the complex nucleon structure in terms of partonic degrees of freedom of QCD • Transverse Momentum Distributions (TMDs) of quarks • Spin and spin-azimuthal asymmetries in semi-inclusive DIS • Tests of partonic description • Spin-azimuthal asymmetries • Double spin asymmetries • Future measurements • From JLab12 → EIC • Summary 2 JLab, Jan 2010

  3. Twist-3 Transverse Momentum Dependent (TMD) Distributions Quark polarization Twist-2 f1u(x,kT) Nucleon polarization Real and imaginary parts of the DL≠0 interference contributions • Factorization of kT-dependent PDFs proven at low PT of hadrons (Ji et al) JLab, Jan 2010

  4. Beam polarization Target polarization SIDIS kinematical plane and observables U unpolarized L long.polarized T trans.polarized sin2f moment of the cross section for unpolarized beam and longitudinal target JLab, Jan 2010

  5. fs y PT fS= p/2+fh fS fh x fh y PT fS=p x Collins mechanism for SSA PT FC fragmentation of transversely polarized quarks into unpolarized hadrons FC fh Fragmenting quark polarization x HT function related to force on the quark. M.Burkardt (2008) 5 JLab, Jan 2010

  6. Sivers mechanisms for SSA fS - HT asymmetries (T-odd) PT FS Correlation between quark transverse momentum and the proton spin fkT Proton polarization x No leading twist, provide access to quark-gluon correlations 6 JLab, Jan 2010

  7. SIDIS: partonic cross sections kT p┴ PT = p┴+zkT 7 JLab, Jan 2010

  8. Double spin asymmetries and flavor decomposition Parallel electron & quark spins Anti-parallel electron & quark spins HERMES u-quarks are mainly aligned with proton spin (Du>0) JLab, Jan 2010

  9. 2 SIDIS with JLab at 6 GeV Scattering of 5.7 GeV electrons off polarized proton and deuteron targets • DIS kinematics, Q2>1 GeV2, W2>4 GeV2, y<0.85 • 0.4>z>0.7, MX2>2 GeV2 epX Large PT range and full coverage in azimuthal angle f crucial for studies 9 JLab, Jan 2010

  10. Target Single-Spin Asymmetry in Semi-Inclusiven↑(e, e’p+/-) E06-010: Reaction on a Transversely Polarized 3He Target • First measurement of the neutron Collins and Sivers asymmetries in SIDIS. • High density polarized 3He target. • Run in Hall A from 10/24/08-2/5/09. 110 shift workers, 7 Ph.D. students. 16o g* BigBite 30o HRSL p pt ~ 65% (proposal 42%) e’ Polarized 3He Target e Cell: Maureen Cell: Astral JLab, Jan 2010

  11. CLAS configuration: EG2000 ep→e’pX e Longitudinaly polarized target • Polarizations: • Beam: ~70% • NH3 proton ~70% • Target position -55cm • Torus +/-2250 • Beam energy ~5.7 GeV p- p+ • Polarized NH3/ND3 ( ~5 days) • Polarized NH3/ND3 with IC 60 days 11 JLab, Jan 2010

  12. E00-108: Leading-Order x-z factorization Hall-C GRV & CTEQ, @ LO or NLO Good description for p and d targets for 0.4 < z < 0.65 Closed (open) symbols reflect data after (before) events from coherent r production are subtracted JLab, Jan 2010

  13. constituent quark model (Pasquini et al). A1 PT-dependence in SIDIS m02=0.25GeV2 mD2=0.2GeV2 M.Anselmino et al hep-ph/0608048 (2004) In perturbative limit predicted to be constant 0.79 0.74 0.74 p+ ALL can be explained in terms of broader kT distributions for f1 compared to g1 JLab, Jan 2010

  14. Quark distributions at large kT: models q Dq JMR model MR, R=s,a u+<u- Effect of the orbital motion on the q- may be significant (H.A.,S.Brodsky, A.Deur,F.Yuan 2007) Higher probability to find a quark anti-aligned with proton spin at large kT 14 JLab, Jan 2010

  15. Quark distributions at large kT: lattice Higher probability to find a quark anti-aligned with proton spin at large kT B.Musch arXiv:0907.2381 Higher probability to find a d-quark at large kT 15 JLab, Jan 2010

  16. Fits to unpolarized data Anselmino et al Collins et al Extracting widths from A1 Assuming the widths of f1/g1 x,z and flavor independent EMC JLab, Jan 2010

  17. Lattice Anselmino Collins A1 PT-dependence A1 CLAS data suggests that width of g1 is less than the width of f1 New eg1dvcs data allow multidimensional binning to study kT-dependence for fixed x JLab, Jan 2010

  18. kT -distributionsin nuclei bigger effect at large z Hall-C CLAS PT = p┴+zkT Higher probability to find a hadron at large PT in nuclei kT-distributions may be wider in nuclei? 18 JLab, Jan 2010

  19. Longitudinal Target SSA measurements at CLAS ~10% of E05-113 data CLAS-2009 (E05-113) CLAS PRELIMINARY ep→e’pX p1sinf+p2sin2f CLAS-2000 W2>4 GeV2 Q2>1.1 GeV2 y<0.85 p1= 0.059±0.010 p2=-0.041±0.010 p1=-0.042±0.015 p2=-0.052±0.016 p1=0.082±0.018 p2=0.012±0.019 MX>1.4 GeV PT<1 GeV 0.12<x<0.48 0.4<z<0.7 Data consistent with negative sin2f for p+ 19 19 JLab, Jan 2010

  20. Kotzinian-Mulders asymmetry curves, cQSM from Efremov et al CLAS 2009 (projected) Transversely polarized quarks in the longitudinally polarized nucleon Worm gear • Measurement of SSAs for pions, provides access to the RSMT TMD (Ralston-Soper (1979), Mulders-Tangerman (1995) • Study Collins fragmentation with longitudinally polarized target 20 JLab, Jan 2010

  21. What we know about ? Boffi et al, Phys. Rev. D 78 (2008) 034025 21 JLab, Jan 2010

  22. genuine effect of intrinsic transverse momentum of quarks GPDs Intrinsic transverse momentum densities of the nucleon Ph. Haegler et al arXiv:0908.1283 PhH, B. Musch et al. arXiv:0908.1283 down up JLab, Jan 2010

  23. CLAS transversely polarized HD-Ice target HD-Ice target vs std nuclear targets Heat extraction is accomplished with thin aluminum wires running through the target (can operate at T~500-750mK) • Pros • Small field (∫Bdl~0.005-0.05Tm) • Small dilution (fraction of events from polarized material) • Less radiation length • Less nuclear background (no nuclear attenuation) • Wider acceptance • much better FOM, especially for deuteron • Cons • HD target is highly complex and there is a need for redundancy due to the very long polarizing times (months). • Need to demonstrate that the target can remain polarized for long periods with an electron beam with currents of order of 1-2 nA • Additional shielding of Moller electrons necessary (use minitorus) HD-Ice target at ~2nA ~ NH3 at 5 nA 23 JLab, Jan 2010 Trento, Nov 12

  24. Collins SSAs CLAS E08-015 Anselmino et al (2007) Boffi et al (2009) helicity-transversity=pretzelosity CLAS with a transversely polarized target will allow measurements of transverse spin distributions and constrain Collins fragmentation function 24 JLab, Jan 2010

  25. Q2 EIC EIC JLab12 Electroproduction kinematics: JLab12→EIC collider experiments H1, ZEUS 10-4<xB<0.02 gluons (and quarks) EIC 10-4<xB<0.3 fixed target experiments COMPASS 0.006<xB<0.3 HERMES 0.02<xB<0.3 gluons/valence and sea quarks JLab  0.1<xB<0.7JLab@12GeV valence quarks Study of high x domain requires high luminosity, low x higher energies JLab, Jan 2010

  26. CLAS12 Wide detector and physics acceptance (current/target fragmentation) LTCC PCAL Lumi = 1035cm-2s-1 High beam polarization 80% High target polarization 85% NH3 (30 days) ND3 (50 days) EC HTCC FTOF Replace 2 sectors of LTCC with a proximity RICH detector to identify Kaons approved by JLab PAC34 JLab, Jan 2010

  27. Hall-A: Experimental Setup and parameters e+3He→e’+p(K)+X G. Cates, E. Cisbani, G.B. Franklin, B. Wojtsekhowski JLab/HallA 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 JLab, Jan 2010

  28. E09-002: Executive Summary Hafidi,Gaskell,Dutta Experiment: Measure Charged pion electroproduction in semi inclusive DIS off deuterium SHMS • Conditions: • 11 GeV electron beam • 10 cm long Liquid deuterium target • Hall C SHMS for electron detection • Hall C HMS for charged pion detection • 17 days of beam time HMS Objectives: Extract charge symmetry violating valence PDFs (δd – δu) as function of x for different Q2 bins. Where and 28 JLab, Jan 2010

  29. E12-09-007 Flavor decomposition using CLAS12 K.Hafidi et al 10% systematics on asymmetries JLab, Jan 2010

  30. Transverse Momentum Dependence of Semi-Inclusive Pion Production PR12-09-017 (Mkrtchyan,Bosted,Ent) Significant net orbital angular momentum of valence quarks implies significant transverse momentum of quarks PR12-09-017: Map the pT dependence (pT ~ L < 0.5 GeV) of p+ and p- production off proton and deuteron targets to measure the kT dependence of up and down quarks Can only be done using spectrometer setup capable of %-type measurements (an essential ingredient of the global SIDIS program!) 2.9 < Mx2 < 7.8 GeV2 Beam time request: 32 days of beam time in Hall C Spin-off: Radiative correction modeling for (e,e’p) Single-spin asymmetries at low pT (< 0.2 GeV) Low-energy (x,z) factorization for kaons JLab, Jan 2010

  31. A1 PT-dependence in SIDIS E12-07-107 Perturbative limit calculations available for : J.Zhou, F.Yuan, Z Liang: arXiv:0909.2238 M.Anselmino et al hep-ph/0608048 m02=0.25GeV2 mD2=0.2GeV2 • ALL(p) sensitive to difference in kT distributions for f1 and g1 • Wide range in PT allows studies of transition from TMD to perturbative approach 31 JLab, Jan 2010

  32. e p 5-GeV 50 GeV - Boer-Mulders Asymmetry with CLAS12 & EIC E12-06-112 Transversely polarized quarks in the unpolarized nucleon sin(fC) =cos(2fh) CLAS12 EIC Perturbative limit calculations available for : J.Zhou, F.Yuan, Z Liang: arXiv:0909.2238 Nonperturbative TMD Perturbative region CLAS12 and EICstudies of transition from non-perturbative to perturbative regime will provide complementary info on spin-orbit correlations and test unified theory (Ji et al) JLab, Jan 2010

  33. Q2-dependence of beam SSA ssinfLU(UL) ~FLU(UL)~ 1/Q (Twist-3) 1/Qbehavior expected (fixed x bin) CLAS: E12-06-112 Hall-C: E12-06-104 R.Ent & H.Mkrtchyan Study R and FL Study for Q2 dependence of beam SSA allows to check the higher twist nature and access quark-gluon correlations. JLab, Jan 2010

  34. PT-dependence of beam SSA E12-06-112 ssinfLU(UL) ~FLU(UL)~ 1/Q (Twist-3) In the perturbative limit 1/PT behavior expected 4x60 100 days, L=1033cm-2s-1 Perturbative region Nonperturbative TMD Study for SSA transition from non-perturbative to perturbative regime. EIC will significantly increase the PT range. JLab, Jan 2010

  35. Study the reaction mechanism in SIDIS x=0.4,z=0.5 CLAS12 PR10-010 Puckett et al • Check the NLO predictions in the collinear approximation • Provide input to the analysis of other SIDIS experiments in JLab JLab, Jan 2010

  36. Summary Measurements of azimuthal dependences of multiplicities as well as double and single spin asymmetries indicate that correlations between spin and transverse motion of quarks may be significant. PT-dependences of the double and single-spin asymmetries provide important input for studies of flavor and helicity dependence of quark transverse momentum dependent distributions. JLab SIDIS experiments at 6 GeV will significantly improve the statistical precision of longitudinally polarized target data, and will provide new data on transversely polarized target. Large kinematical acceptance of CLAS12@ 11 GeV with L=1035cm-2sec-1 combined with high luminosity L=1037cm-2sec-1 precision measurements at Hall-A/C would allow JLab12 to study in details the 3D structure of the nucleon in the valence region. JLab, Jan 2010

  37. Support slides…. JLab, Jan 2010

  38. Transverse momentum dependence of SIDIS General formalism for (e,e’h) coincidence reaction w. polarized beam: [A. Bacchetta et al., JHEP 0702 (2007) 093] (f = azimuthal angle of e’ around the electron beam axis w.r.t. an arbitrary fixed direction) JLab, Jan 2010

  39. CLAS12: Kinematical coverage epX SIDIS kinematics Q2>1GeV2 W2>4 GeV2(10) y<0.85 MX>2GeV x=0.3 → Q2=~2 GeV2 (CLAS), ~5 GeV2 (HERMES) ~15 GeV2 (COMPASS) Large Q2 accessible with CLAS12 are important for separation of HT contributions JLab, Jan 2010

  40. Rpd-for any z, x! Factorization studies Simple LO picture in valence region: Rpd+for any z, pt (if d and u have same pt dependence)! 40 JLab, Jan 2010 Trento, Nov 12

  41. SSA with long. polarized target quark polarization JLab, Jan 2010

  42. SSA with long. polarized target quark polarization JLab, Jan 2010

  43. SSA with unpolarized target quark polarization JLab, Jan 2010

  44. SSA with unpolarized target quark polarization JLab, Jan 2010

  45. Azimuthal moments with unpolarized target quark polarization 45 JLab, Jan 2010 JLab, Nov 25

  46. Azimuthal moments with unpolarized target quark polarization 46 JLab, Jan 2010 JLab, Nov 25

  47. SSA with unpolarized target quark polarization 47 JLab, Jan 2010 JLab, Nov 25

  48. SSA with unpolarized target quark polarization 48 JLab, Jan 2010 JLab, Nov 25

  49. More lattice studies d-quark has wider kT-distribution d-quark opposite to u JLab, Jan 2010

  50. A1 PT-dependence in SIDIS 0.4<z<0.7 M.Anselmino et al hep-ph/0608048 m02=0.25GeV2 mD2=0.2GeV2 p+ A1 suggests broader kT distributions for f1 than for g1 p- A1 may require non-Gaussian kT-dependence for different helicities and/or flavors JLab, Jan 2010

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