Prospects for GPD and TMD studies at the JLab Upgrade Volker D. Burkert Jefferson Lab QCDN’06 Workshop, June 12-16, 2006, Rome  Introduction  JLab Upgrade and CLAS12  GPDs from DVCS and DVMP  TMDs from SIDIS and SSA  Summary

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

Link to the Quark Structure of the Nucleon dxxH q (x, ,t) = H q (t) +  2 D q (t) ∫ 1 dxxE q (x, ,t) = E q (t) -  2 D q (t) ∫ 1 Quark distributions in transverse space, and orbital angular momentum distribution. Distribution of the forces on quarks in transverse space. finite t

JLab Upgrade to 12 GeV EnergyCHL-2 Enhance equipment in existing halls Add new hall 12 GeV Beam polarization P e > 80% E= 2.2, 4.4, 6.6, 8.8, 11 GeV

CLAS12 EC TOF Cerenkov Torus Drift Chambers Cerenkov Central Detector Beamline IEC Design luminosity = cm -2 s -1  Nearly full angle coverage for tracking and  n  detection  High luminosity, cm -2 s -1  Concurrent measurement of deeply virtual exclusive, semi-inclusive, and inclusive processes.

CLAS12 Beamline 5m

CLAS12 – Central Detector Cryostat vacuum jacket Main coil (B 0 = 5T) TOF light-guide Central TOF SiliconTracker Space for e.m. calorimeter Compensation coil

CLAS 12 - Expected Performance Forward DetectorCentral Detector Angular coverage: Tracks (inbending) 8 o - 40 o 40 o o Tracks (outbending) 5 o - 40 o 40 o o Photons 2 o - 40 o 40 o o Track resolution:  p (GeV/c) 0.003p p 2  p T =0.03p T  (mr) 2.5 GeV/c)8 (1 GeV/c)  (mr) 2.5 GeV/c) 2 (1 GeV/c) Photon detection: Energy range > 150 MeV > 60 MeV  E/E 0.09(EC)/0.04(IEC) 0.06 (1 GeV)  (mr) 4 (1 GeV)15 (1 GeV) Neutron detection:  eff 0.5 (EC), 0.1 (TOF)0.04 (TOF) Particle id: e/  >>1000 ( < 5 GeV/c) - >100 ( > 5 GeV/c) -  /K (4  ) < 3 GeV/c (TOF)0.65 GeV/c GeV/c (CC)  p  5 GeV/c (TOF)1.2 GeV/c GeV/c (CC) K/p(  ) < 3.5 GeV/c (TOF)0.9 GeV/c

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

DVCS DVMP GPDs – Flavor separation hard vertices hard gluon Photons cannot separate u/d quark contributions. long. only M =     select H, E, for u/d flavors M = , K select H, E

Q 2 > 2.5 GeV 2 Forward Detector Central Detector ep e  p Acceptance for DVCS, SIDIS ep e  + X x B = 0.35 EC IEC Q2Q2 

DVCS/BH- Beam Asymmetry With large acceptance, measure large Q 2, x B, t ranges simultaneously. A(Q 2,x B,t)  (Q 2,x B,t)  (Q 2,x B,t) E e = 11 GeV A LU

CLAS12 - DVCS/BH- Beam Asymmetry Luminosity = 720fb -1 E e = 11 GeV Q 2 =5.5GeV 2 x B = t = 0.25 GeV 2

CLAS12 - DVCS/BH Beam Asymmetry L = 1x10 35 T = 2000 hrs  Q 2 = 1 GeV 2  x = 0.05 E = 11 GeV Selected Kinematics  LU ~sin  Im{F 1 H +.  }d  e p ep 

GPD H from projected DVCS A LU data b val =b sea =1 MRST02 NNLO distribution Q 2 =3.5 GeV 2  Other kinematics measured concurrently 

CLAS12 - DVCS/BH Target Asymmetry e p ep  Longitudinally polarized target  ~sin  Im{F 1 H +  (F 1 +F 2 ) H... }d  ~ E = 11 GeV L = 2x10 35 cm -2 s -1 T = 1000 hrs  Q 2 = 1GeV 2  x = 0.05 Provide precision measurements of polarized GPD

CLAS12 - DVCS/BH Target Asymmetry  Asymmetries highly sensitive to the u-quark contributions to the proton spin. Transverse polarized target e p ep   ~ sin  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 the scattering plane A UTy Target polarization perpendicular to the scattering plane

CLAS12 – L/T Separation ep ep        LL TT x B = t = GeV 2 Other bins measured concurrently Projections for 11 GeV (sample kinematics)  Test of Bjorken scaling  Power corrections?

Exclusive   production on transverse target A ~ 2H u + H d B ~ 2E u + E d 00 K. Goeke, M.V. Polyakov, M. Vanderhaeghen, 2001 Q 2 =5 GeV 2 E u, E d probes the orbital motion of quarks. 00 B A ~ H u - H d B ~ E u - E d ++ 2  (Im(AB*))/  T          t/4m 2 ) - Re      UT 

W p u (x,k,r) “Parent” Wigner distributions d2kTd2kT (FT) GPDs: H p u (x, ,t), E p u (x, ,t),… GPD Measure momentum transfer to nucleon. Probability to find a quark u in a nucleon P with a certain polarization in a position r and momentum k TMD PDFs: f p u (x,k T ),g 1,f ┴ 1T, h ┴ 1L d3rd3r Measure momentum transfer to quark. TMD Transverse Momentum Dependent PDFs (TMDs)

SIDIS at leading twist e e e p p Sivers transversity Mulders Boer 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)

SIDIS Azimuthal Asymmetry - Sivers effect  Probes orbital angular momentum of quarks by measuring the imaginary part of s-p-wave interference in the amplitude. Hadrons from struck quark have the same sign SSA Opposite effect in target fragmentation T (P /M)A UT sin  s ) T

CLAS12 - Sivers function from A UT (  0 ) F 1T =∑ q e q 2 f 1T ┴q In large Nc limit: f 1T u = -f 1T d Efremov et al (large x B behavior of f 1T from GPD E) xBxB xBxB CLAS12 projected CLAS12 projected

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

Azimuthal Asymmetry - Collins Effect  UT ~ k h 1 H 1 sin  s ) T  Access to transversity distribution and fragmentation of polarized quarks  Unfavored SSA with opposite sign  No effect in target fragmentation

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 GeV Upgrade - Milestones

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.

New Collaborators are welcome!

Additional Slides

CLAS12

JLab Upgrade - CLAS12 Central Detector Forward Detector Luminosity > cm -2 s -1 Tracking - Drift Chambers, SVT Particle id -  /K/p ToF, - Cerenkov’s -   Calorimetry

Operated by Jefferson Science Associates for the U.S. Department of Energy Conceptual Design (CDR) Research and Development (R&D) 2006 Advanced Conceptual Design (ACD) Project Engineering & Design (PED) 2008 Long Lead Procurement Construction Pre-Ops (beam commissioning) 12 GeV Upgrade: Project Critical Decision (CD)CD-1 Documents CD-0 Mission Need2QFY04 (Actual) CD-1 Preliminary Baseline Range2QFY06(Actual) CD-2A/3A Construction and Performance Baseline of Long Lead Items 4QFY06/3QFY07 CD-2B Performance Baseline4QFY07 CD-3B Start of Construction4QFY08 CD-4 Start of Operations1QFY14 NOTE – schedule shown per Feb 2006 CD-1 Documents, new funding profile received in April, update of project plan in progress Critical Decision–1 Approval in February GeV Upgrade included in DOE 5-Year Business Plan in March 2006

Operated by Jefferson Science Associates for the U.S. Department of Energy 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 GeV Upgrade: Status

Originates in the quark distribution. It is measured in the azimuthal asymmetry with transverse polarized target. Requires: non-trivial phase from the FSI + interference between different helicity states (S. Brodsky) Azimuthal Asymmetry – Sivers Effect f 1T D 1 A UT ~ k sin  s ) T

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.  UL ~ k h 1L H 1 KM TT

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.  UL ~ (1-y) h 1L H 1 KM TT

` CLAS12 -  (1115) Polarization ep e  (p    X (SIDIS) K * (892)K E = 11 GeV

 polarization in the target fragmentation p e Λ 1 2 e’