1. Silvia Niccolai Conseil Scientifique et Technique IPN Orsay 9/2/2015 Status on nucleon structure and future plans at JLab GPDs

2. JLab team: projects and organization of manpower 6 staff: R. Dupré (40%, 60%), M. Guidal (70%, 30%), C. Munoz-Camacho (70%, 20%, 10%), S. Niccolai (90%, 10%), E. Voutier – arrived on 15/1/2015 (80%, 20%), D. Marchand – joining (25%) 2 post-doc: M. Boer (100%), G. Charles (20%, 80%) 4 students: C. Desnault (100%), B. Garillon (100%), M. Hattawy (100%), A. Simonyan (100%) 6 staff: R. Dupré (40%, 60%), M. Guidal (70%, 30%), C. Munoz-Camacho (70%, 20%, 10%), S. Niccolai (90%, 10%), E. Voutier – arrived on 15/1/2015 (80%, 20%), D. Marchand – joining (25%) 2 post-doc: M. Boer (100%), G. Charles (20%, 80%) 4 students: C. Desnault (100%), B. Garillon (100%), M. Hattawy (100%), A. Simonyan (100%) GPDs@JLab (6 & 12 GeV): past, present and short-term future (This talk) Heavy Photon Search experiment (HPS): present (R. Dupré’s talk) Electron-Ion-Collider (EIC): long-term future (M. Guidal’s talk)

3. x ee’ X p  (Q 2 ) Electron-proton scattering: the tool to study nucleon structure ee’ pp’  (t=Q 2 )  1950: Elastic scattering ep→e’p’ ( Hofstadter, Nobel prize 1961)  1967: Deep inelastic scattering (DIS) ep→e’X ( Friedman, Kendall, Taylor, Nobel prize 1990) Discovery of the quarks (or “partons”) Measurement of the momentum and spin distributions of the partons: q(x),  q(x) The proton is not a point-like object Measurement of charge and current distributions of the proton: form factors (F 1 (t), F 2 (t)) Low Q 2 High Q 2

4. x Electron-proton scattering: yesterday ? Form factors: transverse quark distribution in coordinate space Parton distributions: longitudinal quark distribution in momentum space F 1 (t), F 2 (t) q(x),  (x)

5. x Electron-proton scattering: today GPDs: H, E, H, E Fully correlated quark distributions in both coordinate and momentum space ~~ Form factors: transverse quark distribution in coordinate space Accessible in hard exclusive processes Parton distributions: longitudinal quark distribution in momentum space q(x),  (x) F 1 (t), F 2 (t)

6. GPDs can be accessed via exclusive electroproduction (final state known) at high transferred momentum (Q 2 ) → virtual-photon scattering at the quark level Generalized parton distributions (GPDs) Correlations between position, momentum and spin of partons in the nucleon, quarks’ angular momentum, nucleon tomography,… DVCS (Deeply Virtual Compton Scattering) eN→eN  x z Small cross sections (~pb) Multi-particle final state 4 GPDs for each quark flavor Several observables needed Each GPD depends on 3 variables High-intensity electron beam Large-acceptance detectors and/or high-resolution detectors working at high luminosity Polarized beam and targets Phenomenological work: observables → GPDs (Q 2 ) e ** GPDs (H, H, E, E)  or meson) N N’ e’ ~~ t x+ξ x-ξ   0,x  ),(Ex q  2 1 Hxdx q  J q  1 1  )0,,( Angular momentum sum rule

7. Hall C (SOS/HMS) Hall B: CLAS Large acceptance Suited for multi-particle final states L~10 34 Hall A: 2 HRS High resolution High luminosity (L~10 37 ) Limited coverage A BC E max ~ 6.0 GeV Polarization 85% Simultaneous delivery to 3 halls Shutdown in May 2012 JLab@6 GeV Continuous Electron Beam Accelerator Facility

8. Hall C (SOS/HMS) A BC JLab@6 GeV Our team has played a leading role in the JLab GPD program for the past ~15 years First GPD proposal presented to PAC - 1998 Spokesperson on all accepted proposals on GPDs at JLab Lead author of ~20 papers on DVCS, meson electroproduction, GPDs extraction and modeling Participated in the running of 7 DVCS experiments at JLab 8 PhD theses defended, 3 ongoing

9. CLAS: DVCS unpolarized and polarized cross sections 21 Q 2 -x B bins, 9 t bins, 24 φ bins Largest kinematic ever covered Two observables extracted BH VGG KM10 KM10a Work by H.S. Jo PRL Draft in the final review stage at CLAS  LU ~ sin  Im{F 1 H +  (F 1 +F 2 ) H -kF 2 E }d  Data taken in 2005 Beam energy ~ 5.75 GeV Beam polarization ~ 80% Target LH 2 Inner Calorimeter (built at IPNO) Beam-spin asymmetry published (PRL100, 162002 (2008) ) ep→epγ →

10. Extraction of Compton Form Factors from DVCS observables 8 CFF M. Guidal: Model-independent fit, at fixed Q 2, x B and t of DVCS observables 8 parameters (the CFFs), loosely bound (+/- 5 x VGG prediction) M. Guidal, Eur. Phys. J. A 37 (2008) 319 & many other papers… GPDs cannot directly be extracted from DVCS observables, one can access Compton Form Factors:

11. xBxB Extraction of CFF from CLAS DVCS pol. and unpol. cross sections Im( H p ), flatter t slope at high x B : faster quarks (valence) at the core of the nucleon, slower quarks (sea) at its periphery → PROTON TOMOGRAPHY xBxB -t VGG predictions using CLAS DVCS c.s. using CLAS DVCS BSA and “old” TSA using Hall A DVCS c.s. CFF fits by M. Guidal Im( H p )

12. The CLAS eg1-dvcs experiment 5 Q 2 -x B bins 4 t bins 10  bins ep→epγ →→ Target: longitudinally polarized NH 3 (polarization ~80%) Data taken from February to September 2009 Beam energy ~5.9 GeV CLAS + IC to detect forward photons Analysis team lead by S. Niccolai 3 DVCS observables extracted: beam-spin asymmetry (BSA) target-spin asymmetry (TSA) double-spin asymmetry (DSA)

13.  UL ~ Im{ H p, H p } ~ Fit:  UL sin  /(1+  cos  ) Target-spin asymmetry from the CLAS eg1-dvcs data E. Seder et al., PRL 114 (2015) 032001 Comparison with world data: Improved statistics x10 at low –t Extended kinematic coverage

14. Extraction of CFF from DVCS TSA, BSA, DSA [12] CLAS BSA (Girod et al.) [14] CLAS TSA (Chen et al.) CFFs fitting code by M. Guidal Im H has steeper t-slope than Im H : is axial charge more “concentrated” than the electromagnetic charge? → PROTON TOMOGRAPHY ~ S. Pisano et al., arXiv:1501.07052, submitted to PRDarXiv:1501.07052 x z

15. DVCS on nuclei: the CLAS eg6 experiment Data taken in the fall 2009 Setup: CLAS+IC+RTPC+ 4 He target Beam energy ~6.065 GeV Goals: coherent and incoherent DVCS Nuclear GPDs, EMC effect Preliminary PhD work by M. Hattawy (R. Dupré, E. Voutier) e 4 He→e 4 He γ → e 4 He→epγX → 4 He spin 0 nucleus, at twist-2 only one CFF in DVCS BSA = 0.11 GeV 2 = 0.18 = 1.5 GeV 2 = 0.7 GeV 2 = 0.27 = 2.22 GeV 2 Radial Time Projection Chamber

16. DVCS in Hall A Results from E00-110 C. Munoz-Camacho et. al., PRL 97, 262002 (2006) Beam-energy separation at constant Q², x B and t: experiments E07-007 (proton) and E08-025 (neutron) Upgraded PbF 2 calorimeter Well described by leading-twist contribution

17. E07-007: Rosenbluth-like separation of DVCS Analysis underway: A. Marti – PhD 2014 (C. Munoz Camacho) missing mass squared Electron acceptance checks using DIS data Working on final global normalizations (multi-tracks, dead-time, radiative corrections) DIS cross-section vs run number M. Defurne, CEA Saclay  Data taken in late 2010  Release of preliminary results expected in the next few months 3 kinematic points: x B =0.36, Q 2 =1.5, 1.75, 2.0 GeV 2 5 bins in t 2 beam energies per point ±5% around expected DIS c.s.

18. PhD work by C. Desnault (C. Munoz Camacho) F. Cano, B. Pire, Eur. Phys. J. A19 (2004) 423 S. Ahmad et al., PR D75 (2007) 094003 VGG, PR D60 (1999) 094017 DVCS on the neutron in Hall A M. Mazouz et al., PRL 99 (2007) 242501 Q²=1.75 GeV², x B =0.36 Data taken in fall 2010 concurrently with E07-007 E08-025, analysis ongoing:  Calibrations completed  Exclusive data isolated  Cross section extraction underway E08-025: Beam-energy « Rosenbluth » separation off the neutron using an LD2 target Important contribution of |DVCS|² term expected in unpolarized cross section

19. S. Morrow et al., Eur. Phys. J. A 39, 5-31, 2009 (  0 @5.75GeV) J. Santoro et al., Phys. Rev. C 78, 025210, 2008 (  @5.75 GeV) L. Morand et al., Eur. Phys. J. A 24, 445-458, 2005 (  @5.75GeV) C. Hadjidakis et al., Phys. Lett. B 605, 256-264, 2005 (  0 @4.2 GeV) K. Lukashin et al., Phys. Rev. C 63, 065205, 2001 (  @4.2 GeV) e1-b (1999) e1-6 (2001) A. Fradi, IPN PhD thesis (2009) (  + @5.75 GeV) e1-DVCS (2005) Vector mesons:  0, ,  and  + → sensitive to the H and E GPDs Deeply virtual meson production at CLAS Pseudoscalar mesons:  → sensitive to transversity GPDs I. Bedlinskiy et al., Phys. Rev. Lett. 109, 112001, 2012 and Phys. Rev. C 90, 039901, 2014 (  0 @5.75GeV) K. Park et al., Phys. Rev. C 77, 015208, 2008 (  + @5.75 GeV) R. De Masi et al., Phys. Rev. C 77, 042201(R), 2008 (  0 @5.75GeV) B. Garillon, IPN PhD thesis, underway ( f   f   @5.75 GeV) 80% of the CLAS DVMP analyses have direct involvement of the IPN team 00 Analysis by B. Garillon: first time measurement f0f0 f2f2

20. JLab 12-GeV upgradeCHL-2 Add new hall E max (A,B,C) = 11 GeV Upgrade of the accelerator completed JLab12 H1, ZEUS ~ valence region ~ sea/gluon region L-HRS Scattering chamber DVCS experiments at 11 GeV have been approved for each of these three halls. Complementary programs: different kinematic coverage different precisions/resolutions focus on different observables Our team has spokespersons on all approved GPD-based experiments for the 12 GeV era (CLAS12, Hall A and Hall C)

21. E12-06-114: DVCS at 11 GeV in Hall A JLab12 with 3, 4, 5 pass beam (6.6, 8.8, 11.0 GeV) JLab @ 6 GeV Absolute cross-section measurements Test of scaling: Q 2 dependence of d  at fixed x Bj Increased kinematical coverage 1 st experiment to run after the 12-GeV upgrade Started in 2014 continuing in 2015 L-HRS Scattering chamber PbF2 calorimeter C. Munoz Camacho spokesperson

22. BSA for DVCS on the neutron with CLAS12 ed→ e(p)n   CLAS12 + Forward Calorimeter + Neutron Detector -t 0 1.2 BSA -0.20.2 J u =.3, J d =.1 J u =.1, J d =.1 J u =.3, J d =.3 J u =.3, J d =-.1 Model predictions (VGG) for different values of quarks’ angular momentum  80 days of data taking L = 10 35 cm −2 s −1 /nucleon First-time measurement  LU ~ sin  Im{F 1 H +  (F 1 +F 2 ) H -kF 2 E }d  ~ The most sensitive observable to the GPD E S. Niccolai spokesperson

23. Technical project: Central Neutron Detector for CLAS12 Main goal: detection of the recoil neutron in nDVCS → The CND must ensure good neutron/photon discrimination → time resolution of ~150 ps Constraints: limited space, magnetic field (5T) Design of the CND : scintillator barrel, 3 radial layers, 48 bars per layers coupled two-by-two downstream by a “u-turn” lightguide, PMTs upstream Financial support from IN2P3 and HP3 (European 7 th framework) R&D completed (2012) using a prototype  t ~140ps Purchased all components Assembly finished, shipping in June 2015; installation ~2016-2017; experiment ~2018 CND prototype CND assembly

24. E12-13-010: DVCS at 11 GeV in Hall C Energy separation of the DVCS cross section Higher Q²: measurement of higher twist contributions Low-x B extension (thanks to sweeping magnet) 1116-block PbWO 4 calorimeter Sweeping magnet Hall C HMS Tentative running: ~ 2019-20 C. Munoz Camacho spokesperson

25. Conclusions  Recently-developed fitting methods allow to extract CFFs from DVCS observables  We need to measure several p-DVCS and n-DVCS observables over a wide phase space  Our groups is producing a wealth of new results on various DVCS and meson production observables from recent CLAS and Hall-A experiments (on polarized and unpolarized proton, deuterium and 4 He targets), and is leader in the phenomenology of GPDs (M. Guidal)  First tomographic imaging of the quarks’ dynamics in the proton  The 12-GeV-upgraded JLab will be the only facility to perform DVCS experiments in the valence region, for Q 2 up to 11 GeV: scaling tests, extended x B coverage, higher statistics  The Central Neutron Detector for CLAS12, conceived and constructed at IPN, is ready  DVCS experiments on both proton and deuterium targets (polarized and unpolarized) are planned for 3 out of the 4 Halls at JLab@12 GeV, with the leadership of the IPN team  GPDs are a unique tool to explore the internal landscape of the nucleon: 3D quark/gluon imaging of the nucleon orbital angular momentum carried by quarks  Their extraction from experimental data is very difficult: there are 4 GPDs for each quark flavor they depend on 3 variables, only two ( , t) experimentally accessible

26. Timelike Compton Scattering with CLAS12 Exploratory measurement with CLAS@6 GeV TCS: sensitivity to the real part of CFFs Projections for 120 days of running with CLAS12 M. Guidal spokesperson

27. Transverse-target spin asymmetry for p-DVCS is highly sensitive to the u-quark contributions to proton spin. CLAS12: p-DVCS transverse target-spin asymmetry 100 days of beam time Beam pol. = 80% ; target pol. (HDIce) = 60% ; Luminosity = 5x10 33 cm -2 s -1 1< Q 2 < 10 GeV 2, 0.06 <x B < 0.66, ‐ t min < ‐ t < 1.5 GeV 2 Proposal conditionally approved by PAC39 M. Guidal co-spokesperson

28. Properties and “virtues” of GPDs X. Ji, Phy.Rev.Lett.78,610(1997) Link with FFs Forward limit: PDFs (not for E, E) ~ Nucleon tomography Nucleon spin: ½ = ½  +  L +  G J Intrinsic spin of the quarks  ≈ 25% Intrinsic spin on the gluons  G ≈ 0 (??) Orbital angular momentum of the quarks  L ? Quark angular momentum (Ji’s sum rule) M. Burkardt, PRD 62, 71503 (2000)

29. Hall B@12 GeV: CLAS12 High luminosity & large acceptance: Concurrent measurement of deeply virtual exclusive, semi-inclusive, and inclusive processes Central Detector Forward Detector PCAL Acceptance for charged particles: Central (CD), 40 o <  <135 o Forward (FD), 5 o <  <40 o Acceptance for photons: IC 2 o <  <5 o EC, 5 o <  <40 o Design luminosity L ~ 10 35 cm -2 s -1

30. GPDs: where we stand, where we are going Dedicated experiments on DVCS (Hall A, CLAS), show evidence for handbag (twist-2) dominance (asymmetry ~sin  ) and unexpected scaling at Q 2 ~ 2 GeV 2 (Hall A) DVMP experiments ( , ,  0 ) hint that either scaling cannot be reached for Q 2 as low as for DVCS or something is missing in “standard” GPDs parameterizations Model-independent fits need to combine several observables measured with high statistics on a wide kinematic coverage to constrain GPDs Hall A’s first attempt to measure n-DVCS showed the importance of this channel for Ji’s sum rule and the extraction of J q More data needed on DVCS and DVMP:  High Q 2 to verify scaling for DVCS on a wider Q 2 range, and to approach GPD validity regime for DVMP  Wide x B coverage  High accuracy on measured observables (high luminosity required)  Measurements of spin-asymmetries and cross sections on proton and neutron CLAS12 will be the optimal facility for these goals

31. The eg1-dvcs experiment at CLAS Data taken from February to September 2009 Beam energies = 4.735, 5.764, 5.892, 5.967 GeV Beam polarizaton ~ 85% CLAS+IC to detect forward photons Target: longitudinally polarized via DNP (5 Tesla, 1 Kelvin, 140 Ghz microwaves) NH 3 (~80%) and ND 3 (~30%) – Luminosity ~ 5∙10 34 cm -2 s -1 Target polarization monitored by NMR ~75 fb -1 on NH3 (parts A, B), ~25 fb -1 on ND3 (part C) Polarized ammonia Carbon Empty cell C.D. Keith et al., NIM A 501 (2003) 327

32. Extracting n-DVCS from eg1-dvcs data H2 Free proton NH3 Free proton in nuclear medium ND3 Quasi-free proton in deuterium and in heavier nuclear medium ND3 Quasi-free neutron in deuterium and in heavier nuclear medium Calculate DVCS on a “free” neutron n F.-X. Girod et al, PRL. 100 (2008) 162002 Daria Sokhan, Glasgow U

33. Hall B@12 GeV: CLAS12 Forward Detector: TORUS magnet Forward tracker - HT Cherenkov Counter - Drift chambers (3 regions) - LT Cherenkov Counter - Forward ToF System - Preshower calorimeter - E.M. calorimeter (EC) - Inner Calorimeter (IC, not shown) Central Detector: - SOLENOID magnet - Barrel Silicon Tracker - Central Time-of-Flight Proposed upgrades: - Micromegas (CD) - Neutron detector (CD) - RICH detector (FD) - Forward Tagger (FD) Central Detector Forward Detector PCAL

34. The CLAS detector (Hall B) Toroidal magnetic field (6 supercond. coils) Drift chambers (argon/CO 2 gas, 35000 cells) Time-of-flight scintillators Electromagnetic calorimeters Cherenkov Counters (e/  separation) Performances: large acceptance for charged particles 8° 0.3 GeV/c, p  >0.1GeV/c good momentum and angular resolution  p/p ≤0.5% - 1.5%,  ≤ 1 mrad Optimal for measurements of exclusive reactions with multi-particle final states After ~15 years of honored service, CLAS has completed its program in May 2012

35. GTMDs TMDs PDFs GPDs FFs DVCSES SIDIS DIS Impact parameter Transverse momentum Longitudinal momentum Interplay between parton distributions and reaction channels Thanks to C. Lorcé

36. JLAB p,n-DVCS (Bpol.) X-sec Hall B p-DVCS BSA,lTSA,DSA,X-sec Hall A CERN COMPASS p-DVCS X-sec,BSA,BCA, tTSA,lTSA,DSA p-DVCS X-sec,BCA p-DVCS BSA,BCA, tTSA,lTSA,DSA H1/ZEUSHERMES DESY DVCS experiments worldwide

37. Im{ H n, E n, E n }  = x B /(2-x B ) k=-t/4M 2   leptonic plane hadronic plane N’ e’ e Unpolarized beam, longitudinal target:  UL ~ sin  Im{F 1 H +  (F 1 +F 2 )( H + x B /2 E ) –  kF 2 E+… }d  ~ Im{ H p, H p } ~  LU ~ sin  Im{F 1 H +  (F 1 +F 2 ) H -kF 2 E }d  ~ Polarized beam, unpolarized target: Im{ H p, H p, E p } ~ Unpolarized beam, transverse target:  UT ~ sin  Im{k(F 2 H – F 1 E ) + ….. }d  Im{ H p, E p } Sensitivity to GPDs of DVCS spin observables Polarized beam, longitudinal target:  LL ~ (A+Bcos  Re{F 1 H +  (F 1 +F 2 )( H + x B /2 E )…}d  ~ Re{ H p, H p } ~ Im{ H n, H n, E n } ~ Proton Neutron ~ Re{ H n, E n, E n } ~ Im{ H n } ~

38. Deeply Virtual Compton Scattering and GPDs e’ t (Q 2 ) e ** x+ξ x-ξ H, H, E, E (x,ξ,t) ~ ~  p p’ « Handbag » factorization valid in the Bjorken regime: high Q 2,  (fixed x B ), t<<Q 2 Q 2 = - (e-e’) 2 x B = Q 2 /2M  =E e -E e’ x+ξ, x-ξ longitudinal momentum fractions t = (p-p’) 2  x B /(2-x B )   0,x  ),(Ex q  2 1 Hxdx q  J G =  2 1 J q  1 1  )0,,( Quark angular momentum (Ji’s sum rule) X. Ji, Phy.Rev.Lett.78,610(1997) «3D» quark/gluon imaging of the nucleon At leading order, leading twist, chiral-even, quark sector → 4 GPDs for each quark flavor Vector: H (x,ξ,t) Tensor: E (x,ξ,t) Axial-Vector: H (x,ξ,t) Pseudoscalar: E (x,ξ,t) ~ ~ conserve nucleon spin flip nucleon spin

39. Accessing GPDs through DVCS      I( DVCS·BH )  ~ |T DVCS +T BH | 2 I( DVCS·BH ) A =    | BH | 2 + | DVCS | 2 +I  DSA  Only  and t are accessible experimentally Real and imaginary parts of Compton Form Factors

40. DVCS @ CLAS: first pioneering results NON-DEDICATED experiments A(  ) =  sin  +  sin2   → twist-2 (handbag) dominance E e =5.75 GeV = 1.82 GeV 2 = 0.16 = 0.31 GeV 2 BSA, BCA and TSA (T & L) at HERMES: handbag dominance confirmed E e =4.3 GeV Q 2 =1.25 GeV 2 = 0.19 = 0.19 GeV 2 S. Stepanyan et al., PRL 87 (2001) ep→epX S. Chen et al., PRL 97 (2006) Low statistics Limited kinematics Uncertainties on determination of ep  final state ep→ep  BSA ~ Im{ H p, H p, E p } ~ TSA ~ Im{ H p, H p } ~

41. Hall A (JLab): first dedicated DVCS experiment High resolution→exclusivity High luminosity→precision Limited phase space C.M. Camacho et al., PRL 97 (2006) Unpolarized cross section Q 2 evolution→ evidence for scaling = (2.3,-0.28) Formalism of Belitsky, Mueller, Kirchner ep→e  X Fit |BH| 2 Inteference BH-DVCS Polarized cross section difference (small Q 2 range)

42. E08-025: Rosenbluth-like separation off the neutron LD2 data C. Desnault Q²=1.75 GeV², x B =0.36  Beam energy separation off the neutron using an LD2 target  Important contribution of |DVCS|² term expected in unpolarized cross section Analysis ongoing:  Calibrations completed  Exclusive data isolated  Cross section extraction underway Data taken in Fall 2010 concurrently with E07-007

43. DVCS BSA and TSA with CLAS12 & 11 GeV beam 120 days of beam time P beam = 85%, P target = 80% L = 2.10 35 cm ‐ 2 s ‐ 1 1< Q 2 < 10 GeV 2 0.1 <x B < 0.65 ‐ t min < ‐ t < 2.5 GeV 2 Statistical error: 2% to 15% on sin  moments Systematic uncertainties: ~6-8% 85 days of beam time P beam = 85% L = 10 35 cm ‐ 2 s ‐ 1 1< Q 2 < 10 GeV 2 0.1 <x B < 0.65 ‐ t min < ‐ t < 2.5 GeV 2 Statistical error: 1% to 10% on sin  moments Systematic uncertainties: ~6-8%

44. DVCS BSA and TSA with CLAS12 & 11 GeV beam 85 days of beam time P beam = 85% L = 10 35 cm ‐ 2 s ‐ 1 1< Q 2 < 10 GeV 2 0.1 <x B < 0.65 ‐ t min < ‐ t < 2.5 GeV 2 Statistical error: 1% to 10% on sin  moments Systematic uncertainties: ~6-8% Impact of CLAS12 DVCS-BSA data on model- independent fit to extract Im(H)

45. Projections for CLAS12 for H Im Work by M. Guidal

46. Fit By Burkardt (2000) From CFFs to spatial densities Applying a model-dependent “deskewing” factor: Projections for CLAS12 How to go from momentum coordinates (t) to space-time coordinates (b) ? (M. Guidal, H. Moutarde, M. Vanderhagen, Rept.Prog.Phys. 76 (2013) 066202)

47. BSA for DVCS on the neutron with CLAS12 ed→ e(p)n   CLAS12 + Forward Calorimeter + Neutron Detector -t 0 1.2 BSA -0.20.2 80 days of data taking L = 10 35 cm −2 s −1 /nucleon  LU ~ sin  Im{F 1 H +  (F 1 +F 2 ) H -kF 2 E }d  ~ The most sensitive observable to the GPD E First-time measurement Final phases of construction at IPN Orsay

48. Double-spin asymmetry from the CLAS eg1-dvcs data Fit:  LL + LL cos  /(1+  cos  ) Constant term dominated by BH S. Pisano et al., arXiv:1501.07052, submitted to PRDarXiv:1501.07052

49. Target-spin asymmetry from the CLAS eg1-dvcs data E. Seder et al. arXiv:1410.6615, submitted to PRLarXiv:1410.6615E. Seder et al., PRL 114 (2015) 032001 “This paper presents new data on Generalized Parton Distributions (GPDs) obtained through DVCS. The results obtained are by far (at least one order of magnitude) the most accurate and the most extensive to date on the target-spin asymmetry in DVCS. Together with earlier published data on beam-spin asymmetries they will significantly advance our knowledge about GPDs. As such, this work has indeed significant impact on the field of hadronic structure. The fact that insight in the 3D-structure of the nucleon is pushed forward by experiments and analyses today fully merits the attention of a broader audience than that served by the Physical Review journals, and I support the publication in Physical Review Letters.” PRL referee

50. JLab upgrade to 12 GeVCHL-2 Add new hall 12 GeV Beam polarization P e > 80% E= 2.2, 4.4, 6.6, 8.8, 11 GeV Upgrade of the instrumentation of the 3 existing Halls Continuous Electron Beam Accelerator Facility

51. H1, ZEUS JLab Upgrade 11 GeV H1, ZEUS JLab @ 12 GeV 11 GeV 27 GeV 200 GeV W = 2 GeV Study of high x B domain requires high luminosity 0.7 HERMES COMPASS The 12 GeV Upgrade is well matched to studies in the valence-quark regime Kinematic coverage for the 12-GeV upgrade Valence region Sea/gluon region

52. New capabilities in Halls A, B & C High Resolution Spectrometer (HRS) pair and specialized large installation experiments CLAS12: large acceptance, high luminosity Super High Momentum Spectrometer (SHMS) at high luminosity and forward angles A B C DVCS experiments at 11 GeV have been approved for each of these three halls. Complementary programs: different kinematic coverage different precisions/resolutions focus on different observables

53. Beam-spin asymmetry from the CLAS eg1-dvcs data  LU ~ Im{ H p } Fit:  LU sin  /(1+  cos  ) KMM12: Kumericki, Mueller, Murray GK: Goloskokov, Kroll GGL: Gonzalez., Goldstein, Liuti S. Pisano et al., arXiv:1501.07052, submitted to PRDarXiv:1501.07052

54. Double-spin asymmetry from the CLAS eg1-dvcs data LL ~ Re{ H p, H p } ~ Fit:  LL + LL cos  /(1+  cos  ) cos  term small S. Pisano et al., arXiv:1501.07052, submitted to PRDarXiv:1501.07052

55. x GPDs: H, E, H, E Fully correlated quark distributions in both coordinate and momentum space ~~ Form factors: transverse quark distribution in coordinate space Accessible in hard exclusive processes Parton distributions: longitudinal quark distribution in momentum space Electron-proton scattering: today

56. CLAS e1-dvcs: DVCS cross section differences  LU ~ sin  Im{F 1 H +  (F 1 +F 2 ) H -kF 2 E }d  ~ BH VGG (H only) KM10 KM10a PRELIMINARY Work by H.S. Jo PRL Draft in final review stage at CLAS

57. Target-spin asymmetry from the CLAS eg1-dvcs data E. Seder et al. arXiv:1410.6615, submitted to PRLarXiv:1410.6615 Comparison with world data: Improved statistics x10 at low –t Extended kinematic coverage E. Seder et al., PRL 114 (2015) 032001 Fit:  UL sin  /(1+  cos  )

58. Added to the standard CLAS IC (inner calorimeter): 424 lead-tungstate crystals + APD readout BUILT AT IPNO The CLAS e1-DVCS experiment F.X. Girod et al., PRL 100, 162002 (2008) BSA Fit = a sin  /(1+b cos  CLAS e1-dvcs Hall A CLAS @ 4.3 GeV 2 VGG(*) twist-2 VGG(*) twist-2 and 3 Regge model (Laget) (*) Vanderhaegen, Guichon, Guidal ep→epγ → Data taken in the spring 2005 Beam energy ~ 5.75 GeV Beam polarization ~ 80% Target LH 2 (More data taken in 2008, under analysis) BSA ~ Im{ H p, H p, E p } ~