1. Studies of spin-orbit correlations at JLab Harut Avakian (JLab) 1 H. Avakian, LNF, Mar 18 LNF SIDIS working group meeting Frascati March 18

2. H. Avakian, LNF, Mar 18 2 QCD: from testing to understanding Testing stage: pQCD predictions, observables in the kinematics where theory predictions are easier to get (higher energies, 1D picture, leading twist, current fragmentation, IMF) Understanding stage: non-perturbative QCD, strong interactions, observables in the kinematics where most of the data is available (all energies, quark-gluon correlations, orbital motion) nucleon in 3D quark-gluon correlations spin-orbit correlations evolution, factorization hadronization parton distributions strong interactions & quark gluon dynamics spectroscopy, excited states 0h DIS 1h SIDIS/DVMP 2h SIDIS/DVMP production in SIDIS provides access to correlations inaccessible in simple SIDIS target fragmentation entanglement

3. Hadron production in hard scattering x F - momentum in the CM frame x F >0 (current fragmentation) x F <0 (target fragmentation) h LL Karliner, Kharzeev, Ellis & Kotzinian Strikman,Weiss & Schweitzer Anselmino, Barone, Kotzinian X. Artru & Z. Belghobsi Correlations of the spin of the target or/and the momentum and the spin of quarks, combined with final state interactions define the azimuthal distributions of produced particles FSI 3 H. Avakian, LNF, Mar 18

4. Features of partonic 3D non-perturbative distributions transverse position and momentum of partons are correlated with the spin orientations of the parent hadron and the spin of the parton itself transverse position and momentum of partons depend on their flavor transverse position and momentum of partons are correlated with their longitudinal momentum H. Avakian, LNF, Mar 18 4 Understanding of the 3D structure of nucleon requires studies of spin and flavor dependence of quark transverse momentum and space distributions Need a new MC generator “PYTHIA with spin-orbit correlations” to simulate azimuthal and spin correlations in final state hadronic distributions. spin and momentum of struck quarks are correlated with remnant quark-gluon interaction play a crucial role in kinematical distributions of final state hadrons, both in semi-inclusive and exclusive processes L

5. 55 h Leading Twist Generalized PDFs Target fragmentationCurrent fragmentation Fracture Functions xFxF M 0 1 h h PDF GPD k T -dependent PDFsGeneralized PDFs FF DA exclusive semi-inclusive H. Avakian, LNF, Mar 18 Large acceptance detectors would allow simultaneous measurements in full x F - range, including target and current regions of SIDIS and exclusive processes.

6. H. Avakian, LNF, Mar 18 66 Quark distributions at large k T : lattice B.Musch et al arXiv:1011.1213 B.Pasquini et al Distributions of PDFs may depend on flavor and spin (lower fraction aligned with proton spin, and less u-quarks at large k T,b T ) g 1 q =  q=(q + -q - )/2 arXiv:0705.4345 G. Miller et al (2011 )

7. 7 JLab Experimental Halls Polarized target IC Hall B 424 PbWO 4 ~87% ~8% ~1.5% H. Avakian, LNF, Mar 18

8. 8 Quark-gluon correlations: Models vs Lattice Models agree on a large e/f 1 -> large beam SSA Lattice results for u-d can be directly compared to models and data. H. Avakian, LNF, Mar 18 Musch et al, arXiv:1011.1213 CLAS/HERMES Force on the active quark right after scattering (Burkardt) Sergio Anefalos-Pereira

9. H. Avakian, LNF, Mar 18 9 Dihadron asymmetries from CLAS SIDIS (TMDs) DVMP (GPDs) Dihadron double spin asymmetry measured at 6 GeV consistent with DIS CLAS Preliminary S. Anefalos Pereira

10. H. Avakian, LNF, Mar 18 10 Dihadron production at JLAB12 Use the clasDIS (LUND based) generator + FASTMC to study   pairs x F - momentum in the CM frame Dihadron sample defined by SIDIS cuts+x F >0 (CFR) for both hadrons   Wide angular coverage is important SoLIDCLAS12

11. H. Avakian, LNF, Mar 18 11 Accessing transversity in dihadron production at JLab Measurements with polarized protons Measurements with polarized neutrons CLAS12 SoLID

12. H. Avakian, LNF, Mar 18 12 Aybat, Prokudin & Rogers C12-11-111 Large acceptance of CLAS12 allows studies of P T and Q 2 -dependence of SSAs in a wide kinematic range Comparison of JLab12 data with HERMES, COMPASS (and EIC) will pin down the non-trivial Q 2 evolution of Sivers asymmetry.

13. H. Avakian, LNF, Mar 18 13 Sivers effect in the target fragmentation Wide coverage of CLAS12 will allow studies of kinematic dependences of the Sivers effect in target fragmentation region arXiv:1502.02669 P2P2 P1P1

14. H. Avakian, LNF, Mar 18 14 Accessing Sivers TMD in dihadron production at JLab Measurements with polarized protons @ CLAS12 Measurements with polarized neutrons @SOLID Measurements with EIC A. Kotzinian, H. H. Matevosyan, and A. W. Thomas, Phys.Rev.Lett. 113, 062003 (2014), 1403.5562. After integration over the azimuthal angle of total transverse momentum The asymmetry as a function of the relative transverse momentum 1 st harmonic of the cos(  T -  R )  R ≠0 can be ensured, by choosing asymmetric cuts on the minimum values of z1 and z2. arXiv:1502.02669 Proposal for PAC43

15. H. Avakian, LNF, Mar 18 15 Back-to-back hadron (b2b) production in SIDIS The beam–spin asymmetry appears, at leading twist and low transverse momenta, in the deep inelastic inclusive lepto- production of two hadrons, one in the target fragmentation region and one in the current fragmentation region. M. Anselmino, V. Barone and A. Kotzinian, Physics Letters B 713 (2012) Back-to-back hadron production in SIDIS would allow: study SSAs not accessible in SIDIS at leading twist measure fracture functions control the flavor content of the final state hadron in current fragmentation (detecting the target hadron) study correlations in target vs current and access factorization breaking effects (similar to pp case) access quark short-range correlations and  SB (Schweitzer et al)... P2P2 P1P1 Silvia Pisano

16. Target fragmentation region:  production polarization tranfer coefficient 60 days of CLAS12 16 H. Avakian, LNF, Mar 18 probability to produce the hadron h when a quark q is struck in a proton target Measurements of fracture functions opens a new in studies of the structure of the nucleon in general and correlations between current and target fragmentation in particular Large acceptance of CLAS12 and EIC provide a unique possibility to study the nucleon structure in target fragmentation region and correlations of target and current fragmentation regions Jeff Phillips

17. Controlling the flavor content with target-current correlations 17 H. Avakian, LNF, Mar 18 Large acceptance of CLAS12 (and EIC) provide a unique possibility to detect simultaneously hadrons in the forward and backward regions ee’e’ p π X K xFxF

18. 18 3D structure: GPDs H. Avakian, LNF, Mar 18 Spin-azimuthal asymmetries in hard exclusive production of photons and pions give access to underlying GPDs Transverse photon dominates the x- section for exclusive  0 production ep  e’p   CLAS e1dvcs Lattice (QCDSF) DVCS asymmetries measured at HERMES & JLAB More measurements at JLab, Compass

19. t-dependence of H H. Avakian, LNF, Mar 18 19 ~ Unpolarized beam, longitudinal target (TSA) :  UL ~ sin  Im{F 1 H +  (F 1 +F 2 )( H + x B /2 E ) –  kF 2 E+… }d  ~ Im{ H p, H p } ~ GK- GL-

20. H. Avakian, LNF, Mar 18 20 CLAS12 can measure Q 2 dependence of HT SSAs significantly extending the range of CLAS Goldstein, Liuti et al P.Kroll & S. Goloskokov The production amplitude at large Q 2 factorizes into the hard subprocess and GPDs Within the handbag approach  * T   transitions are related to transversity (helicity-flip) GPDs accompanied by a twist-3 pion wave function Hard partonic subprocess t-dependences of H T ep  e’p   predictions (GK) from the upolarized data (CLAS) polarized data (Kim)

21. SSAs in exclusive kaon production H. Avakian, LNF, Mar 18 21 K  asymmetries are predicted to be large and with opposite sign to K  Goloskokov&Kroll Goldstein, Hernandez, & Liuti Exclusive production of K  and K  provide access to different combinations of chiral-odd GPDs Beam and target asymmetries in exclusive production of K  and K  are very sensitive to chiral-odd GPDs. Proposal for PAC43 (A.Kim et al)

22. H. Avakian, LNF, Mar 18 22 K+  separation Detection of K+ p and  - would allow to separate of different final states ( ,K*) q  K+K+

23. Analysis framework Differential input (SIDIS): H. Avakian, LNF, Mar 18 23 bin#xQ2Q2 yWMXMX  zPTPT  N(counts)RC 1... N bin#xQ2Q2 yWMXMX  t  N(counts)RC 1... N The size of the bins will be defined by the TMD/GPD extraction framework Differential input (DVMP): M. Aghasyan et al arXiv:1409.0487 (JHEP)

24. H. Avakian, LNF, Mar 18 24 Summary The main goal of the upgraded JLab 3D program is the study of spin and flavor dependence of transverse space and transverse momentum distributions of quarks. Understanding of target fragmentation and correlations between hadrons in target and current fragmentation regions is important for interpretation of semi-inclusive and exclusive production of hadrons. Identification of Kaons will significantly enhance CLAS12 capabilities to study flavor dependence of transverse distributions in semi-inclusive and exclusive processes. Measurements with unpolarized, longitudinally and transversely polarized targets of hard exclusive and semi-inclusive processes will help to accomplish the CLAS12 program of studies of the 3D structure of the nucleon. Need TMD/CFF extraction framework with controlled systematics.

25. H. Avakian, LNF, Mar 18 25 Support slides….

26. 0 0.5 1.0 P.Schweitzer et al. arXiv:1210.1267 Higher probability to find more sea quarks at large k T Predictions from dynamical model of chiral symmetry breaking [Schweitzer, Strikman, Weiss JHEP 1301 (2013) 163] -- k T (sea) >> k T (valence) -- short-range correlations between partons (small-size q-qbar pairs) -- directly observable in P T -dependence of hadrons in SIDIS Dynamical mechanisms creating nucleon sea? Non-perturbative sea in nucleon due to chiral symmetry breaking -- Large flavor asymmetry dbar > ubar as evidence -- Partonic expression of q-qbar vacuum condensate? -- Related to dynamical mass generation – COMPASS Preliminary h + from D M h (arbitrary units) 0.30 < z < 0.6 = 0.054 =4.57 H. Avakian, LNF, Mar 18 26

27. Exclusive  +/   arXiv:0906.0460 Different transverse moments will give access to different combinations of GPDs H. Avakian, LNF, Mar 18 27

28. Flavor separation of form factors G. Cates et al. PRL 106 (2011) 252003 Q4F2q/Q4F2q/ Q 4 F 1 q 28 H. Avakian, LNF, Mar 18 G. Miller et al (2011 ) space distributions depend on flavor and spin (modify in medium) Quark transverse charge densities inside an unpolarized proton arXiv:1304.5926arXiv:1304.5926 form factors of the nucleon fell off faster in nuclear matter

29. H. Avakian, LNF, Mar 18 29

30. Exclusive kaon production H. Avakian, LNF, Mar 18 30 Exclusive production of K  and K  provide access to different combinations of chiral-odd GPDs Unlike  + the K+ x-section is totally dominated by the transverse photon pole contribution negligible

31. H. Avakian, LNF, Mar 18 31 Transverse momentum dependence of sea quark distributions Understanding of the 3D structure of nucleon requires studies of spin and flavor dependence of quark transverse momentum distributions TMD PDF for a given combination of parton and nucleon spins To apply the TMD formalism to data we need to understand the basic properties of the TMDs at a low scale, determined by non-perturbative QCD interactions Dynamical mechanisms producing intrinsic transverse momentum in the nucleon may be be very different for valence and sea quarks k T -distributions of valence quarks governed by the overall size of the nucleon of ~1fm (bag,light-front,..) sea k T ~vacuum fluctuations (0.3 fm), with significant contribution from short-range forces (ex. flavor structure of the sea) Nucleon could be regarded as a many-body system with short-range correlations induced by the chiral-symmetry breaking interactions. NuSea, Phys.Rev. D64 (2001) 052002

32. Exclusive  0  T – dominates for  0. d  T /dt d  L /dt rates higher for small W M 0+,++ amplitude is important in  T. K 2 ⊥ /Q 2 corrections in the propagators of the hard subprocess amplitude are essential in the description of the cross section at low Q 2. They decrease  by a factor of about 10 at Q 2 ∼ 3GeV 2 H. Avakian, LNF, Mar 18 32

33. 33 Evolution Studies: from JLab12 to EIC Q 2 – dependence of Sivers function is sensitive to the non-perturbative physics Wide range in Q 2 is crucial to study the evolution Study of large x domain requires high luminosity Overlap of EIC and JLab12 in the valence region will be crucial for the TMD program JLab@12GeV (25/50/75)  0.1<x B <0.7 : valence quarks EIC √s = 140, 50, 15 GeV  10 -4 <x B <0.3: gluons and quarks, higher P T and Q 2. Aybat,Prokudin&Rogers hep:1112.4423 Sun & Yuan arXiv:1304.5037 JLab12 EIC@Jlab/BNL EIC@HIAF ENC@FAIR Q2Q2 H. Avakian, LNF, Mar 18

34. 34 K/K* and  separation Due to detector resolution clean separation of different channels ( ,K*) will require detection of 4 particles  

35. Studies of 1D PDFs Strong model and parametrization dependence observed already for 1D PDFs Positivity requirement may change significantly the PDF (need self consistent fits of polarized and unpolarized target data!!!) 35 H. Avakian, LNF, Mar 18 F. Aaron et al., JHEP 1001 (2010) P. Jimenez-Delgado et al (2014), 1403.3355.

36. H. Avakian, LNF, Mar 18 36 Exclusive  separation Detection of the complete final sate allow separation of exclusive  s  

37. Correlations between target and current H. Avakian, LNF, Mar 18 37 L how the remnant system dresses itself up to become a full-fledged hadron correlation with the spin of the target or/and the produced particles

38. The sum rule including the OAM Ji’s quark and gluon kinetic angular momentum can be expressed in terms of twist-2 GPDs. the z-component of the quark kinetic OAM is related to a pure twist-3 GPD (Polyakov et al) C.Lorce, B. Pasquini arXiv:1208.3065 describes the vector distribution of quarks inside a longitudinally polarized target ->related to the z -component of angular momentum. H. Avakian, LNF, Mar 18 38