Nuclear Physics at Jefferson Lab Part III

1. Nuclear Physics at Jefferson Lab Part III R. D. McKeown Jefferson Lab College of William and Mary Taiwan Summer School June 30, 2011

2. Outline • Meson spectroscopy • and confinement • Nucleon tomography • Electron Ion Collider

3. Quantum Numbers of Hybrid Mesons Exotic like Flux tube excitation (and parallel quark spins) lead to exotic JPC Excited Flux Tube Quarks Hybrid Meson like

4. Decay of Exotic Mesons Possible daughters: L=1:a,b,h,f,… L=0:,,,,… The angular momentum in the flux tube stays in one of the daughter mesons (L=1) and (L=0) meson, e.g: quark L=1 flux tube L=1 Example: p1→b1p wp→ (3p)p or wp→ (pg)p simple decay modes such as ,, … are suppressed.

5. Previous “Evidence” for 1-+ Exotic BNL 852 (18 GeVp-) • Results are sensitive to • assumption about background • partial waves • not robust • not supported by COMPASS

6. Graphical Processor Units for LQCD • Crays/BlueGene for Gauge Generation - capability • GPUs for physics measurements - capacity (ARRA)

7. +- 2 +- 0 -+ 1 Hall D@JLab Isovector Meson Spectrum States with Exotic Quantum Numbers Dudek et al.

8. Lattice vs. Models Lattice

9. R. McKeown - MENU10 Hall D

10. Proton Spin Puzzle HERMES [X. Ji, 1997] DIS → DS 0.25

11. Spinning Gluons? RHIC p + p data  gluon polarization Global Fit Well maybe not…. D. de Florian et al., PRL 101 (2008) 072001

12. Proton Spin Puzzle X X [X. Ji, 1997] • Consider orbital angular • momentum  Consider transverse momenta

13. Unified View of Nucleon Structure d2kT drz d3r TMD PDFs f1u(x,kT), .. h1u(x,kT)‏ GPDs/IPDs 6D Dist. Wpu(x,kT,r ) Wigner distributions 3D imaging dx & Fourier Transformation d2kT d2rT Form Factors GE(Q2), GM(Q2)‏ PDFs f1u(x), .. h1u(x)‏ 1D

14. Beyond form factors and quark distributions – Generalized Parton Distributions (GPDs) R. D. McKeown June 15, 2010 X. Ji, D. Mueller, A. Radyushkin (1994-1997) Proton form factors, transversecharge & current densities Structure functions, quark longitudinal momentum & helicity distributions Correlated quark momentum and helicity distributions in transverse space - GPDs ~ ~ 4 GPDs: H(x,x,t), E(x,x,t), H(x,x,t), E(x,x,t)

15. Form factors (sum rules) ] x [ 1 DIS at =t=0 å ò x = q dx H ( x , , t ) F1 ( t )Dirac f.f. q = q H ( x , 0 , 0 ) q ( x ) ] [ 1 å ò x = q dx E ( x , , t ) F2 ( t )Pauli f.f. ~ = D q ( x , 0 , 0 ) q ( x ) H 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 x q q q q H , E , H , E ( x , , t ) 1 1 1 [ ] ò = - J G = x + x J q xdx H q( x , , 0 ) E q( x , , 0 ) 2 2 - 1 X. Ji, Phy.Rev.Lett.78,610(1997) Link to DIS and Elastic Form Factors Angular Momentum Sum Rule

16. Deeply Virtual Compton Scattering (DVCS) hard vertices g x – longitudinal quark momentum fraction x+x x-x 2x – longitudinal momentum transfer –t – Fourier conjugate to transverse impact parameter t 3 dimensional imaging of the nucleon GPDs depend on 3 variables, e.g.H(x, x, t).They describe the internal nucleon dynamics.

17. Extraction of GPD’s Ds 2s s+ - s- s+ + s- A = = Cleanest process: Deeply Virtual Compton Scattering ξ=xB/(2-xB) hard vertices Polarized beam, unpolarized target: H(x,t) ~ DsLU~ sinf{F1H+ ξ(F1+F2)H+kF2E}df t Unpolarized beam, longitudinal target: ~ H(x,t) ~ DsUL~ sinf{F1H+ξ(F1+F2)(H+ξ/(1+ξ)E)}df Unpolarized beam, transverse target: E(x,t) DsUT~ sinf{k(F2H – F1E)}df

18. Universality of GPDs Elastic form factors Real Compton scattering at high t Parton momentum distributions GPDs Deeply Virtual Meson production Deeply Virtual Compton Scattering Single Spin Asymmetries

19. Quark Angular Momentum → Access to quark orbital angular momentum

20. Imaging the Nucleon Fourier transform of H in momentum transfer t x < 0.1 x ~ 0.3 x ~ 0.8 gives transverse spatial distribution of quark (parton) with momentum fraction x

21. DVCS beamasymmetryat 12 GeV CLAS12 sinφ moment of ALU Experimental DVCS program E12-06-119 was approved for the 12 GeV upgrade using polarized beam and polarized targets. ep epg High luminosity and large acceptance allows wide coverage in Q2 < 8 GeV2, xB< 0.65, and t< 1.5GeV2

22. Separate Sivers and Collins effects Sivers angle, effect in distribution function: (fh-fs) = angle of hadron relative to initial quark spin Collins angle, effect in fragmentation function: (fh+fs) = p+(fh-fs’) = angle of hadron relative to final quark spin SIDIS Electroproduction of Pions q target angle hadron angle Scattering Plane e-e’ plane

23. Access TMDs through Semi-Inclusive DIS f1 = Unpolarized Boer-Mulder h1= h1L= Transversity h1T = Polarized Target Sivers f1T= Pretzelosity h1T= Polarized Beam and Target g1 = g1T= SL, ST: Target Polarization; le: Beam Polarization

24. Access TMDs through Semi-Inclusive DIS

25. Transverse Momentum Dependent Parton Distributions (TMDs) Nucleon Spin Quark Spin Leading Twist h1= f1 = Boer-Mulder g1 = h1L= Helicity h1T = f1T= Transversity g1T= h1T= Sivers Pretzelosity

26. A Solenoid Spectrometer for SIDIS SIDIS SSAs depend on 4 variables (x, Q2, z and PT ) Large angular coverage and precision measurement of asymmetries in 4-D phase space are essential.

27. Total 1400 bins in x, Q2, PT and z for 11/8.8 GeV beam. z ranges from 0.3 ~ 0.7, only one z and Q2 bin of 11/8.8 GeV is shown here. π+ projections are shown, similar to the π- . SoLIDTransversity Projected Data

28. 12 GeV Approved Experiments by Physics Topics

29. 12 GeV Approved Experiments by PAC Days

30. Electron Ion Collider NSAC 2007 Long-Range Plan: “An Electron-Ion Collider (EIC)with polarized beams has been embraced by the U.S. nuclear science community as embodying the vision for reaching the next QCD frontier. EIC would provide unique capabilities for the study of QCD well beyond those available at existing facilities worldwide and complementary to those planned for the next generation of accelerators in Europe and Asia.” • JLAB Concept • Initial configuration (mEIC): • 3-11 GeV on 12-60 GeVep/eA collider • fully-polarized, longitudinal and transverse • luminosity: up to few x 1034 e-nucleons cm-2s-1 • Upgradable to higher energies (250 GeV protons)

31. EIC Physics Overview • Hadrons in QCD are relativistic many-body systems, with a fluctuating number of elementary quark/gluon constituents and a very rich structure of the wave function. • With an (M)EIC we enter the region where the many-body nature of hadrons, coupling to vacuum excitations, etc., become manifest and the theoretical methods are those of quantum field theory. An EIC aims to study the sea quarks, gluons, and scale (Q2) dependence. • With 12 GeV we study mostly the valence quark component, which can be described with methods of nuclear physics (fixed number of particles). mEIC EIC 12 GeV

32. Medium Energy EIC@JLab • Three compact rings: • 3 to 11 GeV electron • Up to 12 GeV/c proton (warm) • Up to 60 GeV/c proton (cold)

33. MEIC : Detailed Layout warm ring cold ring

34. EIC Site Plan

35. JLAB EIC Workshops • Nucleon spin and quark-gluon correlations: Transverse spin, quark and gluon orbital motion, semi-inclusive processes (Duke U., March 12-13, 2010 ) • 3D mapping of the glue and sea quarks in the nucleon(Rutgers U., March 14-15, 2010) • 3D tomography of nuclei, quark/gluon propagation and the gluon/sea quark EMC effect (Argonne National Lab, April 7-9, 2010) • Electroweak structure of the nucleon and tests of the Standard Model(College of W&M , May 17-18, 2010) • EIC Detectors/Instrumentation (JLab, June 04-05, 2010) 4/5 will produce white paper for publication

36. General Emergent Theme Experimental study of multidimensional distribution functions that map out the quark/gluon properties of the nucleon, including: (quark) flavor spin and orbital angular momentum longitudinal momentum transverse momentum and position High Luminosity over a range of energies (Challenge to accelerator physics!)

37. 11 + 60 GeV 3+20 GeV SIDIS SSA at EIC Huang, Qian, et al Duke workshop

38. Imaging at Low x

39. Gluon Saturation • Gluon density should saturate • (unitarity) • Access at very high E • Use large nuclei

40. Phase Diagram of Nuclear Matter

41. MEIC & ELIC: Luminosity Vs. CM Energy e + p facilities For 1 km MEIC ring e + A facilities

42. FullAcceptance Detector 7 meters detectors solenoid ion FFQs ion dipole w/ detectors ions IP 0 mrad electrons electron FFQs 50 mrad 2+3 m 2 m 2 m Central detector Detect particles with angles below 0.5obeyond ion FFQs and in arcs. Detect particles with angles down to 0.5obefore ion FFQs. Need 1-2 Tm dipole. TOF Solenoid yoke + Muon Detector RICH or DIRC/LTCC 4-5m Tracking RICH EM Calorimeter HTCC Muon Detector Hadron Calorimeter EM Calorimeter Very-forward detector Large dipole bend @ 20 meter from IP (to correct the 50 mr ion horizontal crossing angle) allows for very-small angle detection (<0.3o) Solenoid yoke + Hadronic Calorimeter 2m 3m 2m

43. EIC Realization Imagined

44. Outlook • The Jefferson Lab electron accelerator is currently a unique world-leading facility for nuclear physics research • 12 GeV upgrade ensures another decade of opportunities • Growing program addressing physics beyond the standard model • Nucleon Tomography is a major future theme • Large future project on the horizon: EIC