H. Avakian, Trento, Oct 11 1 Transversity program at CLAS H.Avakian (JLab) GPD-2010 Trento, Oct 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

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?

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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

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

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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.

H. Avakian, Trento, Oct A 1 P T -dependence in SIDIS M.Anselmino et al hep-ph/  + 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:

H. Avakian, Trento, Oct 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:

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

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

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

H. Avakian, Trento, Oct ~10% of E 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  +

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

H. Avakian, Trento, Oct Beam SSA: A LU from 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 !!!

H. Avakian, Trento, Oct 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

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

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

H. Avakian, Trento, Oct HT and Semi-Exclusive Pion Production A.Afanasev, C.Carlson, C. Wahlquist Phys.Lett.B398: ,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?

H. Avakian, Trento, Oct 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/ K *+ K+K+

H. Avakian, Trento, Oct Small field (∫Bdl~ Tm) 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

H. Avakian, Trento, Oct 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 E (2011)

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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)

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

H. Avakian, Trento, Oct CHL- 2 Beam Current: 90 µA Max Pass energy: 2.2 GeV Max Enery Hall A,B,C: 11 GeV May GeV Accelerator Shutdown starts May 2013 Accelerator Commissioning starts Pre-Ops (beam commissioning) Solenoid 5T DC R1, R2, R3 LTCC HTCC FTOF PCAL EC CLAS12 L = 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 12 GeV and CLAS12

H. Avakian, Trento, Oct E : E : Pion SIDIS E : E : Kaon SIDIS E : E : Pion SIDIS E : E : Kaon SIDIS LOI : LOI : Pion SIDIS LOI : LOI : 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 12 GeV in Hall B

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

H. Avakian, Trento, Oct 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

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

H. Avakian, Trento, Oct 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.

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

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct  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

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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)

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct Support slides….

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct Kaon TMDs 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 CLAS12 will provide a more detailed knowledge of Sivers effect ep  e’K + X S.Arnold et al M. Anselmino et al

H. Avakian, Trento, Oct 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)

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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/  0 2 =0.25GeV 2  D 2 =0.2GeV 2 CLAS PRELIMINARY

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct A 1 P T -dependence in SIDIS M.Anselmino et al hep-ph/ 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:

H. Avakian, Trento, Oct JLab12 EIC ENC Q2Q2 Electroproduction kinematics: JLab12→EIC JLab  0.1<x B <0.7 Study of high x domain requires high luminosity, low x higher energies EIC collider experiments H1, ZEUS <x B <0.02 EIC <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):

H. Avakian, Trento, Oct A LL P T -dependence in SIDIS M.Anselmino et al hep-ph/ 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

H. Avakian, Trento, Oct 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?

H. Avakian, Trento, Oct 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

H. Avakian, Trento, Oct 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 --

H. Avakian, Trento, Oct 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 ?