1. H. Avakian, Trento, Oct 11 1 Transversity program at CLAS H.Avakian (JLab) GPD-2010 Trento, Oct 11-15 Physics motivation k T -effects with unpolarized and longitudinally polarized target data Physics with transversely polarized hadrons and quarks Future studies of 3D PDFs at CLAS at 6 GeV Transverse structure & CLAS12 Summary

2. H. Avakian, Trento, Oct 11 2 Some questions to address What is the shape of k T -distributions? Are there correlations between transverse space and momentum distributions? Can k T -distributions be flavor dependent? Are k T -distributions the same for different spin orientations? How spin-orbit correlations change the momentum distributions? What is the fraction of k T -generated in FSI? How quark-gluon correlations affect transverse momentum and space distributions? How nuclear medium changes k T and b T -distributions? How gluons and sea are distributed in k T How spin-orbit correlations are related to the longitudinal structure and nuclear effects?

3. H. Avakian, Trento, Oct 11 333 Single hadron production in hard scattering Measurements in different kinematical regions for nucleon and nucleus provide complementary information on the complex nucleon structure. x F - momentum in the CM frame x F >0 (current fragmentation) x F <0 (target fragmentation) h h Target fragmentationCurrent fragmentation Fracture Functions xFxF M 0 1 h h TMD GPD k T -dependent PDFsGeneralized PDFs PDF h FF DA exclusivesemi-inclusive semi-exclusive

4. H. Avakian, Trento, Oct 11 44 Structure of the Nucleon d2kTd2kT PDFs q(x),  q(x)… d2rTd2rT x-k T and x-r T correlations define the final x-distributions d2kTd2kT W p u (k,r T ) “Mother” distributions (Wigner, GTMDs,..) d2rTd2rT TMD PDFs q(x,k T ),  q(x,k T )… GPD/IPDs H(x,r T ), H~(x,r T )… In nuclear env. TMDs and GPDs modify

5. H. Avakian, Trento, Oct 11 55 Nucleon TMDs + Higher twist distribution functions quark polarization

6. H. Avakian, Trento, Oct 11 66 Cross section is a function of scale variables x,y,z z SIDIS kinematical plane and observables U unpolarized L long.polarized T trans.polarized Beam polarization Target polarization sin2  moment of the cross section for unpolarized beam and long. polarized target

7. H. Avakian, Trento, Oct 11 77 Scattering of 5.7 GeV electrons off polarized proton and deuteron targets SIDIS with JLab at 6 GeV  DIS kinematics, Q 2 >1 GeV 2, W 2 >4 GeV 2, y<0.85  0.4>z>0.7, M X 2 >2 GeV 2 2 eXeX Large P T range and full coverage in azimuthal angle  crucial for studies

8. H. Avakian, Trento, Oct 11 88 CLAS configurations  e  ep→e’  X  Polarizations:  Beam: ~80%  NH3 proton 80%,ND3 ~30%  HD (H-75%,D-25%) 1)Polarized NH3/ND3 (no IC, ~5 days) 2)Unpolarized H (with IC ~ 60 days) 3)Polarized NH3/ND3 with IC 60 days 10% of data on carbon 4)Polarized HD-Ice (no IC, 25 days) Inner Calorimeter Unpolarized, longitudinally and transversely polarized targets Unpolarized and longitudinally polarized targets HD-Ice 0.05 K 0.6 K 1 K 4K4K

9. H. Avakian, Trento, Oct 11 99 Some analysis topics for latest polarized proton and deuteron target data SIDIS with JLab at 6 GeV Inclusive g1p Inclusive g1d DVCS A UL on proton DVCS A UL on neutron DVCS A LL SIDIS A UL & A LL for pions on proton SIDIS A UL & A LL for pions on deuteron SIDIS A UL & A LL for kaons and   on proton Modifications of azimuthal moments in nuclei Large acceptance of CLAS allows simultaneous measurements of hard exclusive and semi-inclusive reactions providing complementary information on the complex nucleon structure.

10. H. Avakian, Trento, Oct 11 10 A 1 P T -dependence in SIDIS M.Anselmino et al hep-ph/0608048  + A 1 suggests broader k T distributions for f 1 than for g 1  - A 1 may require non-Gaussian k T -dependence for different helicities and/or flavors  0 2 =0.25GeV 2  D 2 =0.2GeV 2 0.4<z<0.7 arXiv:1003.4549

11. H. Avakian, Trento, Oct 11 11 A 1 A 1 P T -dependence CLAS data suggests that width of g 1 is less than the width of f 1 Anselmino Collins Lattice New CLAS data would allow multidimensional binning to study k T -dependence for fixed x PTPT PTPT arXiv:1003.4549

12. H. Avakian, Trento, Oct 11 12 Quark distributions at large k T : lattice B.Musch arXiv:0907.2381 12  u/u (dipole formfactor), J.Ellis, D-S.Hwang, A.Kotzinian JMR model q Dq M R, R=s,a

13. H. Avakian, Trento, Oct 11 13 Quark distributions vs b T B.Musch arXiv:0907.2381 13 What we gain modeling + and – distributions for GPDs? Difference in final distributions when using f 1,g 1 or q+,q-

14. H. Avakian, Trento, Oct 11 14 Quark distributions at large k T : lattice Higher probability to find a d-quark at large k T B.Musch arXiv:0907.2381 H. Mkrtchyan et al.H. Mkrtchyan et al. Phys.Lett.B665:20-25,2008.

15. H. Avakian, Trento, Oct 11 15 ~10% of E05-113 data 15 Longitudinal Target SSA measurements at CLAS p 1 sin  +p 2 sin2  0.12<x<0.48 Q 2 >1.1 GeV 2 P T <1 GeV ep→e’  X W 2 >4 GeV 2 0.4<z<0.7 M X >1.4 GeV y<0.85 p 1 = 0.059±0.010 p 2 =-0.041±0.010 p 1 =-0.042±0.015 p 2 =-0.052±0.016 p 1 =0.082±0.018 p 2 =0.012±0.019 CLAS-2009 (E05-113) CLAS PRELIMINARY CLAS-2000 Data consistent with negative sin2  for  +

16. H. Avakian, Trento, Oct 11 16 Kotzinian-Mulders Asymmetries B.Musch arXiv:0907.2381 B.Pasquini et al, arXiv:0910.1677 HERMES CLAS (5 days) Worm gear TMDs are unique (no analog in GPDs)

17. H. Avakian, Trento, Oct 11 17 Beam SSA: A LU from CLAS @ JLab 0.5<z<0.8 Beam SSA from hadronization (Collins effect) by Schweitzer et al. Photon Sivers Effect Afanasev & Carlson, Metz & Schlegel Beam SSA from initial distribution (Boer-Mulders TMD) F.Yuan using h 1 ┴ from MIT bag model Collins contribution should be suppressed → g┴ wanted !!!

18. H. Avakian, Trento, Oct 11 18 Exclusive     and     from CLAS e p e p  π + π - e - p  e - n  + π+π0π+π0 ++ Measurements of ratios      ,       … J u,J d Gluon exchange at low W suppressed (x-sections for   and   comparable) Quark exchange, which dominates, can be considered as part of SIDIS

19. H. Avakian, Trento, Oct 11 19  + SSA from   + SSA has a significant dependence on the source process   Modulation exist even for vanishing helicity change amplitudes

20. H. Avakian, Trento, Oct 11 20 Exclusive pion beam SSA @CLAS6 Sign flip at z ~ 0.5 At z<0.5 struck quark in neutron

21. H. Avakian, Trento, Oct 11 21 HT and Semi-Exclusive Pion Production A.Afanasev, C.Carlson, C. Wahlquist Phys.Lett.B398:393-399,1997 ++ Fragmentation  + 00 HT effects and exclusive  0 suppressed Dominant contribution to meson wave function is a perturbative one gluon exchange and approach its validity at factor ~3 lower Q 2 than in case of hard exclusive scattering. How big is the rho semi-exclusive production compared to pion?

22. H. Avakian, Trento, Oct 11 22 GPDs from cross section ratios Study ratio observables: K/K*/  +,polarization transfer Different final state mesons filter out different combinations of unpolarized (H,E) and polarized (H,E) GPDs. M.Diehl et al. hep-ph/0506171 K *+ K+K+

23. H. Avakian, Trento, Oct 11 23 1.Small field (∫Bdl~0.005-0.05Tm) 2.Small dilution (fraction of events from polarized material) 3.Less radiation length 4.Less nuclear background (no nuclear attenuation) 5.Wider acceptance CLAS transversely polarized HD-Ice target HD-Ice target vs std nuclear targets

24. H. Avakian, Trento, Oct 11 24 Collins SSAs CLAS with a transversely polarized target will allow measurements of transverse spin distributions and constrain Collins fragmentation function Anselmino et al H.A.,A.Efremov,P.Schweitzer,F.Yuan helicity-transversity=pretzelosity CLAS E08-015 (2011)

25. H. Avakian, Trento, Oct 11 25 Measurement of Sivers function and GPD-E DVCS Transverse asymmetry (function of momentum transfer to proton) is large and has strong sensitivity to GPD - E CLAS will provide a measurements of Sivers asymmetry at large x, where the effect is large and models unconstrained by previous measurements. Meissner, Metz & Goeke (2007) GPD-E=0 (DVCS) (SIDIS) CLAS E08-015

26. H. Avakian, Trento, Oct 11 26 Quark distributions at large k T Higher probability to find a hadron at large P T in nuclei k T -distributions may be wider in nuclei? P T = p ┴ +z k T bigger effect at large z Understanding of modification of k T widths in nuclei is important also for nucleon TMDs

27. H. Avakian, Trento, Oct 11 27 k T and FSI l l’ x,k T proton spectator system The difference is coming from final state interactions (different remnant) Studies of DIS and SIDIS with nuclear targets provide info on k T Tang,Wang & Zhou Phys.Rev.D77:125010,2008 BHS 2002 Collins 2002 Ji,Yuan 2002 lTlT l l’ x,k’ T l’ T spectator system nucleus total transverse momentum broadening squared soft gluon exchanges included in the distribution function (gauge link)

28. H. Avakian, Trento, Oct 11 28 Modification of Cahn effect Bag model arXiv:1001.3146 Gao, Liang & Wang Nuclear modification of Cahn may provide info on k T broadening and proton TMDs 28

29. H. Avakian, Trento, Oct 11 29 CHL- 2 Beam Current: 90 µA Max Pass energy: 2.2 GeV Max Enery Hall A,B,C: 11 GeV May 2012 6 GeV Accelerator Shutdown starts May 2013 Accelerator Commissioning starts 2013-2015 Pre-Ops (beam commissioning) Solenoid 5T DC R1, R2, R3 LTCC HTCC FTOF PCAL EC CLAS12 L = 10 35 cm -2 s -1 Primary goal of experiments using CLAS12: study of the internal nucleon dynamics by accessing GPDs & TMDs  detector tuned for studies of exclusive and semi-inclusive reactions in a wide kinematic range.  Large acceptance detector and high luminosity capabilities CEBAF @ 12 GeV and CLAS12

30. H. Avakian, Trento, Oct 11 30 E12-06-112: E12-06-112: Pion SIDIS E12-09-008: E12-09-008: Kaon SIDIS E12-07-107: E12-07-107: Pion SIDIS E12-09-009: E12-09-009: Kaon SIDIS LOI12-06-108: LOI12-06-108: Pion SIDIS LOI12-09-004: LOI12-09-004: Kaon SIDIS PAC approved experiments & LoI N q U L T  Complete program of TMDs studies for pions and kaons  Kaon measurements crucial for a better understanding of the TMDs “kaon puzzle”  Kaon SIDIS program requires an upgrade of the CLAS12 detector PID  RICH detector to replace LTCC Project under development TMDs program @ 12 GeV in Hall B

31. H. Avakian, Trento, Oct 11 31 K/K* and  separations Detection of K+ crucial for separation of different final states ( ,K*)

32. H. Avakian, Trento, Oct 11 32 CLAS12: Kinematical coverage Large Q 2 accessible with CLAS12 are important for separation of HT contributions Q 2 >1GeV 2 W 2 >4 GeV 2 (10) y<0.85 M X >2GeV SIDIS kinematics eXeX

33. H. Avakian, Trento, Oct 11 33 Longitudinally polarized target: Double spin asymmetries

34. H. Avakian, Trento, Oct 11 34 Collins fragmentation: Longitudinally polarized target Study the Collins function of kaons Provides independent information on the RSMT TMD Kotzinian-Mulders Asymmetry protondeuteron Pasquini et al.

35. H. Avakian, Trento, Oct 11 35 Pretzelosity @ CLAS12: CLAS12 will provide pretzelosity measurement in the valence region for Kaons and pions. B. PasquiniB. Pasquini et al. arXiv:0806.2298 Exciting relation: (in bag & spectator model) helicity - transversity = ‘measure’ of relativistic effects

36. H. Avakian, Trento, Oct 11 36 Nonperturbative TMD Perturbative region P T -dependence of beam SSA  sin  LU(UL) ~F LU(UL) ~ 1/Q (Twist-3) 1/P T Check of the higher twist nature of observed SSA critical SSA test transition from non-perturbative to perturbative region 1/Q

37. H. Avakian, Trento, Oct 11 37 Sivers effect in the target fragmentation A.Kotzinian High statistics of CLAS12 will allow studies of kinematic dependences of the Sivers effect in target fragmentation region x F >0 (current fragmentation) x F <0 (target fragmentation) Fracture Functions M h

38. H. Avakian, Trento, Oct 11 38  production in the target fragmentation x F - momentum in the CM frame Combination of CLAS12 and EIC would allow studies of hadronization in the target fragmentation region (fracture functions) in a wide range of x  polarization in TFR provides information on contribution of strange sea to proton spin Study polarized diquark fracture functions sensitive to the correlations between struck quark transverse momentum and the diquark spin. xF()xF() EICCLAS12 (ud)-diquark is a spin and isospin singlet s-quark carries whole spin of  Sivers-2009

39. H. Avakian, Trento, Oct 11 39 Deeply Virtual Compton Scattering ep→e’p’  GPD combinations accessible as azimuthal moments of the total cross section. DVCS BH  LU  ~ sin  {F 1 H( , t) +  (F 1 +F 2 ) H +kF 2 E } ~ Polarized beam, unpolarized target: Unpolarized beam, longitudinal target:  UL  ~ sin  {F 1 H +  (F 1 +F 2 )( H +.. } ~ Unpolarized beam, transverse target:  UT  ~ cos  {k(F 2 H – F 1 E ) + ….  }  = x B /(2-x B ),k = t/4M2 Kinematically suppressed

40. H. Avakian, Trento, Oct 11 40 CLAS12 - DVCS/BH Target Asymmetry Transversely polarized target e p ep   UT  ~ cos  Im{k 1 (F 2 H – F 1 E ) +…}d  Q 2 =2.2 GeV 2, x B = 0.25, -t = 0.5GeV 2 E = 11 GeV Sample kinematics A UTx Target polarization in scattering plane A UTy Target polarization perpendicular to scattering plane DVCS Transverse asymmetry (function of momentum transfer to proton) is large and has strong sensitivity to GPD - E Meissner, Metz & Goeke (2007)

41. H. Avakian, Trento, Oct 11 41 Summary CLAS longitudinally polarized NH3 and ND3 target data provides superior sample of events allowing detailed studies of single and double spin asymmetries using multidimensional bins Measurements of spin and azimuthal asymmetries with unpolarized, longitudinally polarized and transversely polarized targets in semi-inclusive processes at JLab : Measure TMDs of partons in the valence region Provide detailed info on partonic spin-orbit correlations Study quark-gluon correlations (HT) Study nuclear modification of 3D PDFs CLAS12 will significantly increase the luminosity, kinematical coverage and particle identification capabilities of CLAS6

42. H. Avakian, Trento, Oct 11 42 Support slides….

43. H. Avakian, Trento, Oct 11 43 SSA in ep->e’  X Strange pattern:  0 SSA bigger at very low and very large z HERMES 27.5 GeV CLAS 5.7 GeV

44. H. Avakian, Trento, Oct 11 44 Quark distributions at large k T Higher probability to find a hadron at large P T in nuclei k T -distributions may be wider in nuclei? P T = p ┴ +z k T bigger effect at large z Understanding of modification of k T widths in nuclei is important also for nucleon TMDs

45. H. Avakian, Trento, Oct 11 45 HDice polarized targets of solid hydrogen,  +HD (E06-101); e+HD (E08-021) polarize to frozen-spin state at 12 mK, 15 tesla in new HDice Lab transfer to CLAS In-Beam-Cryostat renovated Lab in Test Lab Annex installing polarizing equip assembling Oxford dilution fridge - training SC magnet new NMR electronics under test - optimize H  D spin transfer fabricating CLAS target cells HD purity analysis  prep time - chromatography & Raman scat    HDice Lab Hall B

46. H. Avakian, Trento, Oct 11 46 HDice In-Beam Cryostat for CLAS HDice Transfer Cryostat designed for both  (Start Counter) and e - (mini-Torus) ASME code review nearly complete under construction 0.05 K 0.6 K 1 K1 K 4 K4 K HDice IBC-CLAS loading    HDice In-Beam Cryostat

47. H. Avakian, Trento, Oct 11 47 Kaon TMDs program @ 12 GeV in Hall B K+K+ K-K- -- ++ K + ampl. >  + ampl. Unespected from u-quark dominance! How large can the effect of s quarks be? HERMES coll. PRL 103 (2009)  /K measurement @ CLAS12 will provide a more detailed knowledge of Sivers effect ep  e’K + X S.Arnold et al. 0805.2137 M. Anselmino et al. 0805.2677

48. H. Avakian, Trento, Oct 11 48 k T and FSI l l’ x,k T proton spectator system The difference is coming from final state interactions (different remnant) Studies of DIS and SIDIS with nuclear targets provide info on k T Tang,Wang & Zhou Phys.Rev.D77:125010,2008 BHS 2002 Collins 2002 Ji,Yuan 2002 lTlT l l’ x,k’ T l’ T spectator system nucleus total transverse momentum broadening squared ~4 n, with ~4-6 MeV soft gluon exchanges included in the distribution function (gauge link)

49. H. Avakian, Trento, Oct 11 49 CLAS slightly lower, but may have bigger Anselmino et al from EMC data → = 0.25 Wider at smaller beam energies? Transverse momentum distributions of hadrons Gauss 49

50. H. Avakian, Trento, Oct 11 50 cos  moment in A LL -P T -dependence P T -dependence of cos  moment of double spin asymmetry is most sensitive to k T - distributions of quarks with spin orientations along and opposite to the proton spin. hep-ph/0608048  0 2 =0.25GeV 2  D 2 =0.2GeV 2 CLAS PRELIMINARY

51. H. Avakian, Trento, Oct 11 51 Jet limit: Higher Twist azimuthal asymmetries No leading twist, provide access to quark- gluon correlations T-odd H.A.,A.Efremov,P.Schweitzer,F.Yuan Phys.Rev.D81:074035,2010 “interaction dependent” Twist-2 Twist-3

52. H. Avakian, Trento, Oct 11 52 A 1 P T -dependence in SIDIS M.Anselmino et al hep-ph/0608048 A LL  ) sensitive to difference in k T distributions for f 1 and g 1 Wide range in P T allows studies of transition from TMD to perturbative approach  0 2 =0.25GeV 2  D 2 =0.2GeV 2 Perturbative limit calculations available for : J.Zhou, F.Yuan, Z Liang: arXiv:0909.2238

53. H. Avakian, Trento, Oct 11 53 JLab12 EIC ENC Q2Q2 Electroproduction kinematics: JLab12→EIC JLab  0.1<x B <0.7 JLab@12GeV Study of high x domain requires high luminosity, low x higher energies EIC collider experiments H1, ZEUS 10 -4 <x B <0.02 EIC 10 -4 <x B <0.3 gluons (and quarks) fixed target experiments COMPASS  0.006<x B <0.3 HERMES  0.02<xB<0.3 gluons/valence and sea quarks valence quarks EIC (4x60): ENC (3x15):

54. H. Avakian, Trento, Oct 11 54 A LL P T -dependence in SIDIS M.Anselmino et al hep-ph/0608048 New experiment with 10 times more data will study the P T -dependence for different quark helicities and flavors for bins in x to check if  0 <  2  0 2 =0.25GeV 2  D 2 =0.2GeV 2 0.4<z<0.7 E05-113

55. H. Avakian, Trento, Oct 11 55 H. Avakian, JLab, May 3 55 SIDIS: partonic cross sections kTkT P T = p ┴ +z k T p┴p┴ Ji,Ma,Yuan Phys.Rev.D71:034005,2005 Is the info on x-k T correlations accessible in k T integrated observables?

56. H. Avakian, Trento, Oct 11 56 Extracting widths from A 1 Assuming the widths of f 1 /g 1 x,z and flavor independent Anselmino et al Collins et al Fits to unpolarized data EMC

57. H. Avakian, Trento, Oct 11 57 Dilution factor in SIDIS Multiple scattering and attenuation in nuclear environment introduces additional P T -dependence for hadrons Fraction of events from polarized hydrogen in NH3 N u,N p -total counts from NH3 and carbon normalized by lumi  u,  p -total areal thickness of hydrogen (in NH3), and carbon target Cn=Nitr/Carbon ratio (~0.98) Diff. symbols for diff x-bins --

58. H. Avakian, Trento, Oct 11 58 EMC Effect I. Cloet (Argonne-2010) NJL-model In medium quarks are more relativistic  q more sensitive to angular momentum  Lower components of wavefunctions more enhanced  Lower components carry more angular mom. 58 H. Avakian, JLab, May 3 In medium modification  Mass, magnetic moment, size  Form factors, PDFs, GPDs, TMDs, etc How sensitive are inclusive measurements to the transverse structure of nucleon and nucleus ?