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Harut Avakian (JLab)

SIDIS at EIC. Harut Avakian (JLab). Gluons and the quark sea at high energies , INT Nov 9, 2010. TMDs and spin-orbit correlations P T -distributions Higher twists in SIDIS Nuclear modifications Kaons vs pions MC-simulations Projections for observables Conclusions.

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Harut Avakian (JLab)

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  1. SIDIS at EIC Harut Avakian (JLab) Gluons and the quark sea at high energies , INT Nov 9, 2010 • TMDs and spin-orbit correlations • PT-distributions • Higher twists in SIDIS • Nuclear modifications • Kaons vs pions • MC-simulations • Projections for observables • Conclusions H. Avakian, INT, Nov 9

  2. Single hadron production in hard scattering Target fragmentation Current fragmentation semi-inclusive exclusive semi-exclusive h h FF h DA DA h M PDF GPD PDF 1 -1 xF 0 Fracture Functions kT-dependent PDFs Generalized PDFs xF>0 (current fragmentation) h xF<0 (target fragmentation) xF- momentum in the CM frame Measurements in different kinematical regions provide complementary information on the complex nucleon structure. 2 H. Avakian, INT, Nov 9

  3. kT-dependent PDFs and FFs: “new testament” No analog in twist-2 appear in sinf moment of ALU and AUL Baccetta, Diehl, Goeke, Metz, Mulders, Schlegel EPJ-2007 quark-gluon-quark correlations responsible for azimuthal moments in the cross section H. Avakian, INT, Nov 9

  4. Q2 EIC EIC JLab12 Electroproduction kinematics: JLab12→EIC collider experiments EIC (4x60): H1, ZEUS 10-4<xB<0.02 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 EIC 10-4<xB<0.3 gluons (and quarks) • wide range of Q2 for a fixed x • wide range of PT • small x region • wide range of Q2 for a fixed x • wide range of PT • small x region EIC provides access to: H. Avakian, INT, Nov 9

  5. SIDIS: partonic cross sections kT p┴ PT = p┴+zkT Ji,Ma,Yuan Phys.Rev.D71:034005,2005 How sensitive are SIDIS observables to x-kT correlations? 5 H. Avakian, INT, Nov 9

  6. Quark distributions at large kT: lattice Higher probability to find a d-quark at large kT B.Musch et al arXiv:1011.1213 Higher probability to find a quark anti-aligned with proton spin at large kT and bT B.Pasquini et al 6 H. Avakian, INT, Nov 9

  7. Quark distributions at large kT: lattice q Dq JMR model MR, R=s,a B.Musch et al arXiv:1011.1213 Du/u Sign change of Du/u consistent between lattice and diquark model 7 H. Avakian, INT, Nov 9

  8. H. Avakian, INT, Nov 9

  9. Hadronic PT-distriutions NJL model, H.Matevosyan H. Mkrtchyan et al.Phys.Lett.B665:20-25,2008. 9 9 H. Avakian, INT, Nov 9

  10. Flavor decomposition in SIDIS SIDIS COMPASS HERMES DIS Frascati, Oct 17 COMPASS COMPASS data only HERMES DIS vs SIDIS → additional hadron detection. 10 H. Avakian, INT, Nov 9

  11. Acceptances and efficiencies HERMES EIC How acceptance in f and PT affect the A1 and Ds extractions in SIDIS? 11 H. Avakian, INT, Nov 9 H.Avakian, JLab, Oct 29

  12. cosf moment in ALL-PT-dependence hep-ph/0608048 m02=0.25GeV2 mD2=0.2GeV2 CLAS PRELIMINARY PT-dependence of cosf moment of double spin asymmetry is most sensitive to kT-distributions of quarks with spin orientations along and opposite to the proton spin. 12 H. Avakian, INT, Nov 9

  13. Lattice Anselmino Collins A1 PT-dependence arXiv:1003.4549 A1 PT PT CLAS data suggests that width of g1 is less than the width of f1 New CLAS data would allow multidimensional binning to study kT-dependence for fixed x H. Avakian, INT, Nov 9

  14. A1 PT-dependence in SIDIS 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 14 H. Avakian, INT, Nov 9

  15. Beam SSA for exclusive pions W2>4 GeV2,Q2>1 GeV2 Sign flip at z ~ 0.5 4.3 GeV -t < 0.5GeV2 5.7 GeV At z>0.5 struck quark in pion LUND-MC 15 H. Avakian, INT, Nov 9

  16. Beam SSA: ALU from COMPASS & HERMES CLAS @4.3 &5.7GeV No x-dependence? Change the sign at low z? 16 H. Avakian, INT, Nov 9

  17. SSA at large xF 0 moves to lower xF with energy? ANL s=4.9 GeV BNL s=6.6 GeV RHIC s=62.4 GeV FNAL s=19.4 GeV H. Avakian, INT, Nov 9

  18. Beam SSA: ALU from CLAS @ JLab Photon Sivers Effect Afanasev & Carlson, Metz & Schlegel, Gamberg et al. Beam SSA from initial distribution(Boer-Mulders TMD) F.Yuan using h1┴ from MIT bag model 0.5<z<0.8 Beam SSA from hadronization (Collins effect) by Schweitzer et al. Collins contribution should be suppressed → g┴ wanted !!! 18 H. Avakian, INT, Nov 9

  19. Compare single hadron and dihadron SSAs fh y Only 2 terms with common unknown HT G~ term! PT fS=p x Chiral odd HT-distribution How can we separate the HT contributions? HT function related to force on the quark. M.Burkardt (2008) M.Radici H. Avakian, INT, Nov 9

  20. Jet limit: Higher Twist azimuthal asymmetries H.A.,A.Efremov,P.Schweitzer,F.Yuan arXiv:1001.5467 Twist-2 Twist-3 “interaction dependent” No leading twist, provide access to quark-gluon correlations First data available from lattice! 20 H. Avakian, INT, Nov 9

  21. Modification of Cahn effect Bag model arXiv:1001.3146 total transverse momentum broadening squared Gao, Liang & Wang • Nuclear modification of Cahn may provide info on kT broadening and proton TMDs • Large cosnf moments observed at COMPASS H. Avakian, INT, Nov 9

  22. LEPTO/PEPSI: quark distributions Event Generator with polarized electron and nucleon: PEPSI,…. MC with Cahn Acceptance check Design parameters Smearing/resolution routines Use GEANT as input z>0.1 Physics analysis using the “reconstructed” event sample z>0.3 • Implemented in PEPSI modification to LEPTO done by A. Kotzinian • Add different widths for q+ and q- Need to model TMDs in LUND MC H. Avakian, INT, Nov 9

  23. EIC MC simulations Different MC used in EIC simulations are consistent (Xin Qian) H. Avakian, INT, Nov 9

  24. PT-dependence of beam SSA ssinfLU~FLU~ 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. H. Avakian, INT, Nov 9

  25. Q2-dependence of beam SSA ssinfLU(UL) ~FLU(UL)~ 1/Q (Twist-3) 1/Qbehavior expected (fixed x bin) Study for Q2 dependence of beam SSA allows to check the higher twist nature and access quark-gluon correlations. H. Avakian, INT, Nov 9

  26. Sivers effect: pion electroproduction GRV98, Kretzer FF (4par) S. Arnold et al arXiv:0805.2137 M. Anselmino et al arXiv:0805.2677 GRV98, DSS FF (8par) • EIC measurements at small x will pin down sea contributions to Sivers function H. Avakian, INT, Nov 9

  27. Sivers effect: Kaon electroproduction EIC CLAS12 • At small x of EIC Kaon relative rates higher, making it ideal place to study the Sivers asymmetry in Kaon production (in particular K-). • Combination with CLAS12 data will provide almost complete x-range. H. Avakian, INT, Nov 9

  28. Sivers effect: sea contributions GRV98, DSS FF M. Anselmino et al arXiv:0805.2677 GRV98, Kretzer FF S. Arnold et al arXiv:0805.2137 • Negative Kaons most sensitive to sea contributions. • Biggest uncertainty in experimental measurements (K- suppressed at large x). H. Avakian, INT, Nov 9

  29. CLAS12 EIC4x60 Kaon production in SIDIS FAST-MC L S S* detected s(p) = 0.05 + 0.06*p [GeV] % Identification using the missing mass may be possible H. Avakian, INT, Nov 9

  30. EIC 4x60 (Lumi 1033,cm-2sec-1 , ~1 hour) <x>=0.1, <Q2>=4 s(p) = 0.05 + 0.06*p [GeV] % K*s can be studied with EIC H. Avakian, INT, Nov 9

  31. Kaon <cos2f> @ HERMES 31 H. Avakian, INT, Nov 9 H.Avakian, JLab, Oct 29

  32. Collins asymmetry - proton “Kaon puzzle” in spin-orbit correlations Is there a link between HERMES and BRAHMS Kaon vs pion moments (K- has the same sign as K+ and pi+, comparable with K+)? 32 H. Avakian, INT, Nov 9

  33. Collins effect kicked in the opposite to the leading pion(into the page) L Sub-leading pion opposite to leading (double kick into the page) Simple string fragmentation (Artru model) p+ Leading pion out of page ( - direction ) z L p- If unfavored Collins fragmentation dominates measured p- vs p+, why K- vs K+ is different? 33 33 H. Avakian, INT, Nov 9

  34. e p 5-GeV 50 GeV - Boer-Mulders Asymmetry with CLAS12 & EIC 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) H. Avakian, INT, Nov 9

  35. sUL ~ KM From CLAS12 to EIC: Kotzinian-Mulders Effect Transversely polarized quarks in the longitudinally polarized nucleon Worm gear Study Collins fragmentation using transversely polarized quarks in a longitudinally polarized nucleon. H. Avakian, INT, Nov 9

  36. positivity bound Pretzelosity @ EIC 5x50 epX p- p+ helicity-transversity=pretzelosity In models (bag, diquark) pretzelosity defines the OAM • EIC measurement combined with CLAS12 will provide a complete kinematic range for pretzelosity measurements H. Avakian, INT, Nov 9

  37. Collins Effect: from asymmetries to distributions need Combined analysis of Collins fragmentation asymmetries from proton and deuteron may provide independent to e+e- (BELLE/BABAR) Information on the underlying Collins function. H. Avakian, INT, Nov 9

  38. J.Ellis, D.Kharzeev, A. Kotzinian ‘96 W.Melnitchouk and A.W.Thomas ‘96 L production in the target fragmentation L polarization in TFR provides information on contribution of strange sea to proton spin (ud)-diquark is a spin and isospin singlet s-quark carries whole spin of L xF- momentum in the CM frame xF(L) Study polarized diquark fracture functions sensitive to the correlations between struck quark transverse momentum and the diquark spin. EIC CLAS12 Wide kinematical coverage of EIC would allow studies of hadronization in the target fragmentation region (fracture functions) H. Avakian, INT, Nov 9

  39. Sivers effect in the target fragmentation A.Kotzinian Separation of current and target fragmentation at EIC will allow studies of kinematic dependences of the Sivers effect in target fragmentation region xF>0 (current fragmentation) xF<0 (target fragmentation) h M Fracture Functions 39 H. Avakian, INT, Nov 9

  40. Summary • Studies of spin and azimuthal asymmetries in semi-inclusive processes at EIC : • Provide detailed info on partonic spin-orbit correlations • Measure transverse momentum distributions of partons at small x, in a wide range of Q. • Study quark-gluon correlations (HT) in nucleon and nucleus • Need realistic MC simulations (LUND,Geant) to check sensitivity to various effects related to the transverse structure of the nucleon • Need more theory (+lattice) support for HT • EIC: Measurements related to the spin, spin orbit and quark-gluon correlations combined with JLab12 HERMES,COMPASS, RHIC,BELLE,BABAR,Fermilab,J-PARC,GSI data will help construct a more complete picture about the spin structure of the nucleon beyond the collinear approximation. H. Avakian, INT, Nov 9

  41. Support slides…. H. Avakian, INT, Nov 9

  42. H. Avakian, INT, Nov 9

  43. MC simulations using NJL H. Avakian, INT, Nov 9

  44. M.Osipenko H. Avakian, INT, Nov 9

  45. Tang,Wang & Zhou Phys.Rev.D77:125010,2008 l’ l l’ l total transverse momentum broadening squared kT and FSI BHS 2002 Collins 2002 Ji,Yuan 2002 x,kT lT x,k’T l’T spectator system spectator system proton nucleus soft gluon exchanges included in the distribution function (gauge link) • The difference is coming from final state interactions (different remnant) H. Avakian, INT, Nov 9

  46. Nuclear broadening Hadronic PT-distriutions Large PT may have significant nuclear contribution 46 46 H. Avakian, INT, Nov 9

  47. Azimuthal moments with unpolarized target quark polarization 47 H. Avakian, INT, Nov 9 JLab, Nov 25

  48. Azimuthal moments with unpolarized target quark polarization 48 H. Avakian, INT, Nov 9 JLab, Nov 25

  49. SSA with unpolarized target quark polarization 49 H. Avakian, INT, Nov 9 JLab, Nov 25

  50. SSA with unpolarized target quark polarization 50 H. Avakian, INT, Nov 9 JLab, Nov 25

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