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Prospects for GPD and TMD studies at the JLab Upgrade

Prospects for GPD and TMD studies at the JLab Upgrade. Volker D. Burkert* ) Jefferson Lab. Introduction JLab Upgrade and CLAS12 GPDs from DVCS and DVMP TMDs from SIDIS and SSA Summary. * ) Talk presented by H.Avakian. QCDN’06 Workshop, June 12-16, 2006, Rome. 3-D Scotty. z.

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Prospects for GPD and TMD studies at the JLab Upgrade

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  1. Prospects for GPD and TMD studies at the JLab Upgrade Volker D. Burkert*) Jefferson Lab • Introduction • JLab Upgrade and CLAS12 • GPDs from DVCS and DVMP • TMDs from SIDIS and SSA • Summary *) Talk presented by H.Avakian QCDN’06 Workshop, June 12-16, 2006, Rome

  2. 3-D Scotty z 2-D Scotty z x y 1-D Scotty Water Calcium probablity Carbon x x GPDs, TMDs & PDFs This Workshop – GPDs, TMDs Deeply Inelastic Scattering, PDFs

  3. Wpu(x,k,r) “Parent” Wigner distributions d3r TMD TMD PDFs: fpu(x,kT),g1,f┴1T, h┴1L Measure momentum transfer to quark. Generalized PDFs (GPDs & TMDs) Probability to find a quark u in a nucleon P with a certain polarization in a position r and momentum k d2kT (FT) GPD GPDs: Hpu(x,x,t), Epu(x,x,t),… Measure momentum transfer to nucleon. • Provide complementary information on structure of nucleon • Studies require detection of multiparticle final states

  4. Add new hall CHL-2 Enhance equipment in existing halls E= 2.2, 4.4, 6.6, 8.8, 11 GeV Beam polarization Pe > 80% JLab Upgrade to 12 GeV Energy 12 GeV

  5. CLAS12 • Nearly full angle coverage for tracking and g, ndetection • High luminosity, 1035 cm-2s-1 • Concurrent measurement • of deeply virtual exclusive, • semi-inclusive, and inclusive • processes. EC Cerenkov Drift Chambers TOF Cerenkov Torus Central Detector Beamline IEC Design luminosity = 1035cm-2s-1

  6. 5m CLAS12 Beamline

  7. CLAS 12- Expected Performance Forward Detector Central Detector Angular coverage: Tracks (inbending) 8o - 40o 40o - 135o Tracks (outbending) 5o - 40o 40o - 135o Photons 2o - 40o 40o - 135o Track resolution: dp (GeV/c) 0.003p + 0.001p2 dpT=0.03pT dq (mr) < 1 (>2.5 GeV/c) 8 (1 GeV/c) df (mr) < 3 (> 2.5 GeV/c) 2 (1 GeV/c) Photon detection: Energy range > 150 MeV > 60 MeV dE/E 0.09(EC)/0.04(IEC) 0.06 (1 GeV) dq (mr) 4 (1 GeV) 15 (1 GeV) Neutron detection: heff 0.5 (EC), 0.1 (TOF) 0.04 (TOF) Particle id: e/p >>1000 ( < 5 GeV/c) - >100 ( > 5 GeV/c) - p/K (4s) < 3 GeV/c (TOF) 0.65 GeV/c 3 - 10 GeV/c (CC) p/p (4s) < 5 GeV/c (TOF) 1.2 GeV/c 3 - 10 GeV/c (CC) K/p(4s) < 3.5 GeV/c (TOF) 0.9 GeV/c

  8. H1, ZEUS Deeply Virtual Exclusive Processes - Kinematics Coverage of the 12 GeV Upgrade H1, ZEUS 27 GeV 11 GeV 11 GeV 200 GeV JLab Upgrade JLab @ 12 GeV COMPASS W = 2 GeV HERMES Study of high xB domain requires high luminosity 0.7

  9. GPDs – Flavor separation DVMP DVCS long. only hard gluon hard vertices M = r0/r+ select H, E, for u/d flavors M = p, h, K select H, E Photons cannot separate u/d quark contributions.

  10. ep egp Q2 > 2.5 GeV2 Central Detector Forward Detector ep ep+X Acceptance for DVCS, SIDIS qg xB = 0.35 EC IEC Q2

  11. ALU DVCS/BH- Beam Asymmetry Ee = 11 GeV With large acceptance, measure large Q2, xB, t ranges simultaneously. A(Q2,xB,t) Ds(Q2,xB,t) s(Q2,xB,t)

  12. Ee = 11 GeV Q2=5.5GeV2 xB = 0.35 -t = 0.25 GeV2 CLAS12- DVCS/BH- Beam Asymmetry Luminosity = 720fb-1

  13. CLAS12- DVCS/BH Beam Asymmetry e p epg E = 11 GeV DsLU~sinfIm{F1H+..}df Selected Kinematics L = 1x1035 T = 2000 hrs DQ2 = 1 GeV2 Dx = 0.05

  14. Q2=3.5 GeV2 bval=bsea=1 MRST02 NNLO distribution • Other kinematics measured concurrently GPDHfrom projected DVCS ALU data p

  15. Unphysical JLab12: Hall A with 3, 4, 5 pass beam Absolute measurements: d(e=±1) 250K events/setup H(e,e’)p Twist 2 & Twist 3 separation. Im{DVCS*BH}+DVCS2 Re{DVCS*BH} +’DVCS2 100 days

  16. L = 2x1035 cm-2s-1 T = 1000 hrs DQ2 = 1GeV2 Dx = 0.05 E = 11 GeV CLAS12-DVCS/BH Target Asymmetry e p epg Longitudinally polarized target ~ Ds~sinfIm{F1H+x(F1+F2)H...}df Provide precision measurements of polarized GPD

  17. CLAS12-DVCS/BH Target Asymmetry Sample kinematics e p epg E = 11 GeV Q2=2.2 GeV2, xB = 0.25, -t = 0.5GeV2 Transverse polarized target Ds ~ sinfIm{k1(F2H– F1E) +…}df AUTx Target polarization in the scattering plane AUTy Target polarization perpendicular to the scattering plane • Asymmetries highly sensitive to the u-quark contributions to the proton spin.

  18. xB = 0.3-0.4 -t = 0.2-0.3GeV2 sL sT Other bins measured concurrently CLAS12– L/T Separationep epro (p+p-) Projections for 11 GeV (sample kinematics) • Test of Bjorken scaling • Power corrections?

  19. Q2=5 GeV2 A~ Hu - Hd B ~ Eu - Ed r+ Exclusiver0production on transverse target 2 D (Im(AB*))/p T AUT = - |A|2(1-x2) - |B|2(x2+t/4m2) - Re(AB*)2x2 A ~ 2Hu + Hd r0 B ~ 2Eu + Ed r0 Eu, Edprobes the orbital motion of quarks. B K. Goeke, M.V. Polyakov, M. Vanderhaeghen, 2001

  20. SIDIS at leading twist e Boer e p Mulders e p transversity Sivers Off-diagonal PDFs vanish if quarks only in s-state! In addition T-odd PDFs require FSI(Brodsky et al., Collins, Ji et al. 2002)

  21. PT-dependence of beam SSA In the perturbative limit 1/PT behavior expected EIC 2.0 Perturbative region Non-perturbative TMD PT-dependence of azimuthal moments allows studies of transition from non-perturbative to perturbative description (Unified theory by Ji et al).

  22. sin(f-fs) (P /M)AUT T SIDIS Azimuthal Asymmetry - Sivers effect • Probes orbital angular momentum of quarks by measuring the imaginary part ofs-p-wave interference in the amplitude. • Hadrons from struck quark have the same sign SSA • Opposite effect in target fragmentation T

  23. CLAS12- Sivers function from AUT (p0) Efremov et al (large xB behavior of f1T from GPD E) In large Nc limit: F1T=∑qeq2f1T┴q f1Tu = -f1Td CLAS12 projected CLAS12 projected xB xB

  24. Sivers effect in the target fragmentation xF>0 (current fragmentation) xF<0 (target fragmentation) xF- momentum in the CM frame Wide kinematic coverage of CLAS12 allows studies of hadronization in the target fragmentation region

  25. sin(f+fs) sUT~ k h1H1 T Azimuthal Asymmetry - Collins Effect • Access to transversity distribution and fragmentation of polarized quarks • Unfavored SSA with opposite sign • No effect in target fragmentation

  26. T T sUL ~ k h1LH1 KM Collins Effect and Kotzinian-Mulders Asymmetry Measures the Collins fragmentation with longitudinally polarized target. Access to the real part of s-p wave interference amplitudes.

  27. 12 GeV Upgrade - Milestones • June 2006 Annual Review of Project Progress • August 2006 JLab PAC 30 • First review of 12 GeV proposals – “first 5 years of experiments” • Key first step in identifying the research interests and significant contributions of international and other non-DOE collaborators • October 2006 – start Project Engineering & Design (PED) • 12 GeV is on track for Construction Approval in Sept 2008

  28. Summary • The JLab 12 GeV Upgrade is essential for the study of nucleon structure in the valence region with high precision: • - deeply virtual exclusive processes (DVCS, DVMP) • - semi-inclusive meson production with polarized beam • and polarized targets • Provide new and deeper insight into • - quark orbital angular momentum contributions • to the nucleon spin • - 3D structure of the nucleon’s interior and correlations • - quark flavor polarization • - ….. • CLAS12 will be world wide the only full acceptance, general purpose detector for high luminosity electron scattering experiments, and is essential for the GPD/TMD program.

  29. New Collaborators are welcome!

  30. Additional Slides

  31. CLAS12

  32. CLAS12– Central Detector (B0 = 5T) TOF light-guide Cryostat vacuum jacket Space for e.m. calorimeter SiliconTracker Main coil Compensation coil Central TOF

  33. JLab Upgrade -CLAS12 Luminosity > 1035cm-2s-1 Tracking - Drift Chambers, SVT Particle id - p/K/p ToF, - Cerenkov’s - g/p0 Calorimetry Forward Detector Central Detector

  34. 2004-2005 Conceptual Design (CDR) 2004-2008 Research and Development (R&D) 2006 Advanced Conceptual Design (ACD) 2007-2009 Project Engineering & Design (PED) 2008 Long Lead Procurement 2008-2012 Construction 2012-2013 Pre-Ops (beam commissioning) 12 GeV Upgrade: Project Critical Decision–1 Approval in February 2006 12 GeV Upgrade included in DOE 5-Year Business Plan in March 2006 NOTE – schedule shown per Feb 2006 CD-1 Documents, new funding profile received in April, update of project plan in progress

  35. Near Term: June 2006 Annual Review of Project Progress Focus on progress in last year, and plans for CD-2B Performance Baseline review next year CD-2B Approval anticipated for September 2007 August 2006 JLab PAC 30 First review of 12 GeV proposals – “commissioning experiments” Spokespersons make commitments to construction of equipment Key first step in identifying the research interests and significant contributions of international and other non-DOE collaborators October 2006 – start Project Engineering & Design (PED) 12 GeV is on track for CD-2 in Sept 2007 and CD-3 in Sept 2008 12 GeV Upgrade: Status

  36. Azimuthal Asymmetry – Sivers Effect Originates in the quark distribution. It is measured in the azimuthal asymmetry with transverse polarized target. sin(f-fs) f1TD1 T AUT ~ k Requires: non-trivial phase from the FSI + interference between different helicity states (S. Brodsky)

  37. T T sUL ~ (1-y) h1LH1 KM Collins Effect and Kotzinian-Mulders Asymmetry Measures the Collins fragmentation with longitudinally polarized target. Access to the real part of s-p wave interference amplitudes.

  38. ` CLAS12-L(1115) Polarization E = 11 GeV ep eL(pp-)X (SIDIS) K K*(892)

  39. e 1 Λ p 2 L polarization in the target fragmentation e’

  40. 1 1 ∫ ∫ dxxHq(x,x,t) = Hq(t) + x2Dq(t) dxxEq(x,x,t) = Eq(t) - x2Dq(t) -1 -1 Link to the Quark Structureof the Nucleon finite t Distribution of the forces on quarks in transverse space. Quark distributions in transverse space, and orbital angular momentum distribution.

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