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Physics Program with 12 GeV JLab

Physics Program with 12 GeV JLab. J. P. Chen, Jefferson Lab EIC Workshop, APS-DNP/JPS Joint Meeting, 10/13/2009. Introduction and Overview Nucleon Structure - Spin-Flavor Structure in Valance Region Nucleon Structure - Generalized Parton Distributions

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Physics Program with 12 GeV JLab

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  1. Physics Program with 12 GeV JLab J. P. Chen, Jefferson Lab EIC Workshop, APS-DNP/JPS Joint Meeting, 10/13/2009 • Introduction and Overview • Nucleon Structure - Spin-Flavor Structure in Valance Region • Nucleon Structure - Generalized Parton Distributions • Nucleon Structure - Transverse Momentum Dependent Distributions • Nucleon Structure - Form Factors • Parity Violation Electron Scattering - Low Energy Test of Standard Model • Nuclear Physics: Hadronization, Short-Range Correlations, Few-Body • Exotic Meson Search: Gluon Excitations • Acknowledgement: Some slides “borrowed” from colleague’s talks

  2. QCD and Nucleon Structure • A major challenge in fundamental physics: Understand QCD in all regions, including strong (confinement) region • Nucleon = u u d + sea + gluons • Structure mostly determined by strong interaction • Mass, charge, magnetic moment, spin, axial charge, tensor charge • Decomposition of each of the above fundamental quantities Mass: ~1 GeV, but u/d quark mass only a few MeV each! Momentum: total quarks only carry ~ 50% Spin: ½, total quarks contribution only ~30% Spin Sum Rule Tensor charge Transverse sum rule? • Multi-dimensional structure and distributions • Confinement -- QCD vacuum: gluon field and sea

  3. Jefferson Lab Experimental Halls 6 GeV polarized CW electron beam Pol=85%, I=180mA Luminosity ~ 1039 Polarized ~ 1036 Will be upgraded to 12 GeV by ~ 2014 HallA: two HRS’ Hall B:CLAS Hall C: HMS+SOS

  4. Hall B/C Polarized p/d target Hall A polarized 3He target P=65% @ I=15 uA • Polarized NH3/ND3 targets • Luminosity ~ 1035 (Hall C), ~ 1034 (Hall B) • In-beam average polarization 70-90% for p, 30-40% for d • longitudinal, transverse and vertical • Luminosity = 1036 • P(in-beam) = 65% • Effective polarized neutron

  5. Upgrade magnets and power supplies CHL-2 Enhance equipment in existing halls Add new hall 12 11 6 GeV CEBAF

  6. Experimental Halls (new) Hall D: linear polarized photon beam, Selonoid detetcor GluoX collaboration: exotic meson spectroscopy gluon-quark hybrid, confinement Hall B: CLAS12 GPDs, TMDs, … Hall C: Super HMS + existing HMS Form factors, structure functions, … Hall A: Dedicated devices + existing spectrometers Super BigBite, Solenoid, Moller Spectrometer SIDIS, PVDIS, …

  7. Overview of Physics Program • Gluonic Excitations and the Origin of Confinement • Nucleon Structure • Quark spin-flavor structure in valence region • Deep Exclusive Reactions (DVCS, DVMP) to study GPDs • SIDIS to measure Transversity and TMDs • Form Factors – Constraints on the GPDs • Symmetry Tests • Parity violation to test Standard Model and precision study of hadronic physics • The Physics of Nuclei • Medium Effects: Hadronization, EMC effects • Short-Range Correlations • Few-Body

  8. 12 GeV Upgrade Kinematical Reach Reach a broad DIS region Decisive inclusive DIS measurements at high-x Precision Deep Exclusive Reactions (e.x. DVCS) to study GPDs Precision SIDIS for transversity and TMDs Parity Violating DIS to test Standard Model and precision study of hadronic physics

  9. Structure Functions at High x Valence Quark Distributions

  10. F2n/F2p d/u ratio at high-x Hall A 11 GeV with HRS BONUS at Hall B 11 GeV with CLAS12

  11. JLab 6 GeV Results on A1 at high x Hall A E99-117, PRL 92, 012004 (2004) PRC 70, 065207 (2004) Hall B CLAS, Phys.Lett. B641 (2006) 11 pQCD SU(6)

  12. Polarized Parton Distribution at Large x pQCD with Quark Orbital Angular Momentum Inclusive Hall A and B and Semi-Inclusive Hermes BBS BBS+OAM F. Yuan, H. Avakian, S. Brodsky, and A. Deur, arXiv:0705.1553

  13. Projections for JLab at 11 GeV A1p at 11 GeV pQCD SU(6)

  14. JLab @11 GeV Flavor Decomposition with SIDIS Du and Dd at JLab 11 GeV Polarized Sea

  15. Generalized Parton Distributions 3-d Quark-Gluon Structure of the Nucleon

  16. X. Ji, D. Mueller, A. Radyushkin, … Structure functions, quark longitudinal momentum & helicity distributions Correlated quark momentum and helicity distributions in transverse space - GPDs Beyond form factors and quark distributions – Generalized Parton Distributions (GPDs) M. Burkardt, … Interpretation in impact parameter space Proton form factors, transverse charge & current densities

  17. hard vertices –t – Fourier conjugate to transverse impact parameter H(x,x,t), E(x,x,t), . . GPDs & Deeply Virtual Exclusive Processes “handbag” mechanism Deeply Virtual Compton Scattering (DVCS) x g x – longitudinal quark momentum fraction x+x x-x 2x – longitudinal momentum transfer t xB x = 2-xB

  18. Hall A E00-110 Demonstrated Handbag Dominance at Modest Q2 Twist 2 contribution Twist 3 contribution strongly suppressed The Twist-2 term can be extracted accurately from the cross-section difference Dominance of twist-2  handbag dominance  DVCS interpretation straightforward

  19. overlap with other experiments unique to JLab High xB only reachable with high luminosity H1, ZEUS Upgraded JLab has complementary & unique capabilities Deeply Virtual Exclusive Processes - Kinematics Coverage of the 12 GeV Upgrade JLab Upgrade

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

  21. 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)

  22. Single Spin Asymmetry in Semi-inclusive DIS Transverse Momentum Dependent Distributions

  23. “Leading-Twist” TMD Quark Distributions Nucleon Unpol. Trans. Long. Quark Unpol. Long. Trans.

  24. JLab 6 GeV experiment (E06-010/06-011) SSA in SIDISn↑(e,e′π+/-) on a Transversely Polarized 3He Target Collins Spokespersons: X. Jiang (Los Alamos) J.P. Chen (JLab) E. Cisbani (INFN) H. Gao (Duke) J.-C. Peng (UIUC) PhD Students: K. Allada (UKy) C. Dutta (UKy) J. Huang (MIT) J. Katich (W&M) X. Qian (Duke) Y. Wang (UIUC) Y. Zhang (Lanzhou) Sivers First neutron (3He) measurement Completed data taking in 2/2009

  25. 12 GeV: Solenoid detector for SIDIS and PVDIS GEMs Gas Cerenkov 3He target GEMs Calorimeter

  26. Projection vs PT and x for p+ (60 days) • For one z bin (0.5-0.6) • Will obtain 4 z bins (0.3-0.7) • Also p- at same time • With upgraded PID for K+ and K-

  27. 3-D Projections for Collins and Sivers Asymmetry (p+)

  28. Parity Violating Electron Scattering Test Standard Model and Precision Study of Hadron Structure

  29. Parity Violating DIS A V V A Moller PV is insensitive to the Cij C1u and C1d will be determined to high precision by Qweak, APV Cs C2u and C2d are small and poorly known: one combination can be accessed in PV DIS New physics such as compositeness, leptoquarks: Deviations to C2u and C2d might be fractionally large

  30. PVDIS with SoLID • High Luminosity on LH2 & LD2 • Better than 1% errors for small bins • x-range 0.25-0.75 • Moderate running times

  31. (2C2u-C2d)=0.012 (sin2W)=0.0009 Unique, unmatched constraints on axial-vector quark couplings: Complementary to LHC direct searches • 1 TeV extra gauge bosons (model dependent) • TeV scale leptoquarks with specific chiral couplings Examples: Physics Implications

  32. PV DIS and Nucleon Structure • PVDIS provide precision study of hadron structure: • Higher twist effects • Charge Symmetry Violation (CSV) • d/u at high x • JLab at 11 GeV offers new opportunities • PV DIS can address issues directly • Luminosity and kinematic coverage • Outstanding opportunities for new discoveries • Provide confidence in electroweak measurement

  33. Parity Violating Moller Scattering QWe modified sin2W runs with Q2 (sin2W) ~ 0.0003 Comparable to single collider measurements • Semileptonic processes have • theoretical uncertainties • E158 established running, • probing vector boson loops • JLab measurement would • have impact on • discrepancy between • leptonic and hadronic Z-pole • measurements

  34. Hadronization in Nuclear SIDIS Quark Propagation Through Nuclei

  35. Nuclear Deep Inelastic Scattering and Hadronization • We can learn about hadronization distance scales and reaction mechanisms from semi-inclusive nuclear DIS • Nucleus acts as a spatial filter for outgoing hadronization products Initial focus on properties of leading hadron; correlations with subleading hadrons and soft protons also of interest.

  36. Significant dependence of R on In general, n (GeV) z Observables – Hadronic Multiplicity Ratio (≈ medium-modified fragmentation function) h = p, K, h, w, f, p, .… Must measure multi-variable dependence for stringent model tests! <z>=0.3-0.42, <Q2>=2.2-3.5 <n>=11.5-13.4, <Q2>=2.6-3.1

  37. Each point is differential in Q2, n, z, and A; all are acquired simultaneously 12 GeV Anticipated Data 12 GeV Anticipated Data

  38. Summary • 12 GeV JLab with high luminosity (1039 unpol., 1036-1037 pol.) and large acceptance will lead us to a new precision frontier • Provide precision data on multi-dimension nucleon structure and a deep understanding of strong interaction: • Spin-flavor structure in the valence region • Generalized Parton Distributions with DVCS and limited DVMP • Transverse Spin and TMDs with SIDIS • Parity violating electron scattering provide precision low-energy tests of standard model and a precision tool to study hadronic physics • Precision Study of hadronization and nuclei medium effects • Other important physics opportunities: • GlueX, Form Factors, Short-range Correlations, Few-Body, J/y, …

  39. Strong Interaction and QCD • A major challenge in fundamental physics: Understand QCD in all regions, including strong interaction (confinement) region • Strong interaction, running coupling ~1 -- QCD: accepted theory for strong interaction -- asymptotic freedom (2004 Nobel) perturbation calculation works at high energy -- interaction significant at intermediate energy quark-gluon correlations -- interaction strong at low energy (nucleon size) confinement, chiral symmetry breaking as E

  40. New Hall D, Enhanced Existing Halls A, B & C C D 9 GeV tagged polarized photons and a 4 hermetic detector Super High Momentum Spectrometer (SHMS) at high luminosity and forward angles A B Retain HRS Pair for continuation of research in which resolution comparable to nuclear level spacing is essential. Use Hall to stage “one-of-a-kind” specialized experiments requiring unique apparatus. CLAS upgraded to higher (1035 cm-2s-1) luminosity and coverage

  41. Why Are PDFs at High x Important? • Valence quark dominance: simpler picture -- direct comparison with nucleon structure models SU(6) symmetry, broken SU(6), diquark • x 1 region amenable to pQCD analysis -- hadron helicity conservation? • Clean connection with QCD, via lattice moments • Input for search for physics beyond the Standard Model at high energy collider -- evolution: high x at low Q2 low x at high Q2 -- small uncertainties amplified -- example: HERA ‘anomaly’ (1998) • Input to nuclear, high energy physics calculations

  42. World Data on A1 Proton Neutron

  43. Color “Polarizabilities”

  44. Jlab 6 GeV Results on d2 E08-027 “g2p” SANE 6 GeV Experiments Sane: just completed in Hall C “g2p” in Hall A, 2011 projected “d2n”just completed in Hall A

  45. Color Polarizability d2n with JLab 12 GeV Projections with 12 GeV experiments Improved Lattice Calculation (QCDSF, hep-lat/0506017)

  46. x DIS at =t=0 = - - q H ( x , 0 , 0 ) q ( x ), q ( x ) ~ = D D - q ( x , 0 , 0 ) q ( x ), q ( x ) H Form factors (sum rules) ] [ 1 å ò x = q dx H ( x , , t ) F1 ( t )Dirac f.f. ~ ~ q x q q q q H , E , H , E ( x , , t ) ] [ 1 å ò x = q dx E ( x , , t ) F2 ( t )Pauli f.f. q 1 1 ~ ~ ò ò x = x = q q dx H ( x , , t ) G ( t ) , dx E ( x , , t ) G ( t ) , , A q P q - - 1 1 Quark angular momentum (Ji’s sum rule) [ ] 1 1 1 ò = - JG = x + x q q q J xdx H ( x , , 0 ) E ( x , , 0 ) 2 2 - 1 X. Ji, Phy.Rev.Lett.78,610(1997) Link to DIS and Elastic Form Factors

  47. Quark distribution q(x) Accessed by beam/target spin asymmetry -q(-x) Accessed by cross sections t=0 Access GPDs through DVCS x-section & asymmetries DIS measures at x=0

  48. First GPD analyses of HERA/CLAS/HERMES data in LO/NLOconsistent witha ~ 0.20. A. Freund (2003), A. Belitsky et al. (2003) CLAS preliminary E=5.75 GeV ALU AUL = asinf + bsin2f <Q2> = 2.0GeV2 <x> = 0.3 <-t> = 0.3GeV2 f [rad] DVCS interpreted in pQCD at Q2 > 1 GeV2 Pioneering DVCS experiments Full GPD analysis needs high statistics and broad coverage twist-2 twist-3 twist-3 contributions are small

  49. L = 2x1035 cm-2s-1 T = 1000 hrs DQ2 = 1GeV2 Dx = 0.05 e p epg E = 11 GeV CLAS12-DVCS/BH Target Asymmetry Longitudinally polarized target ~ Ds~sinfIm{F1H+x(F1+F2)H...}df CLAS preliminary AUL E=5.75 GeV <Q2> = 2.0GeV2 <x> = 0.2 <-t> = 0.25GeV2

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

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