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

2 Meson spectroscopy and confinement Nucleon tomography Electron Ion Collider Outline

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

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

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

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

7 States with Exotic Quantum Numbers Isovector Meson Spectrum Hall Dudek et al.

8 Lattice vs. Models Lattice

9 9 R. McKeown - MENU10

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

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

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

13 W p u (x,k T,r ) Wigner distributions d2kTd2kT PDFs f 1 u (x),.. h 1 u (x)‏ GPDs/IPDs d 2 k T dr z d3rd3r TMD PDFs f 1 u (x,k T ),.. h 1 u (x,k T )‏ 3D imaging 6D Dist. Form Factors G E (Q 2 ), G M (Q 2 )‏ d2rTd2rT dx & Fourier Transformation 1D

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

15 Link to DIS and Elastic Form Factors ),,( ~, ~,,txEHEH qqqq  DIS at  =t=0 )()0,0,( ~ )()0,0,( xqx H xqxH q q   Form factors (sum rules)  )(),,( ~, )(),,( ~ ) Dirac f.f.(),,(, 1 1, tGtxEdxtGtxH tF1F1 txH qP q qA q q q          ) Pauli f.f.(),,( 1 tF2F2 txEdx q q          J G =  1 1 )0,, q(q()0,, q(q( xE xHxdxJ q X. Ji, Phy.Rev.Lett.78,610(1997) Angular Momentum Sum Rule

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

17 t hard vertices A =           = Unpolarized beam, transverse target:  UT ~ sin  {k(F 2 H – F 1 E ) }d  E(  t)  LU ~ sin  {F 1 H + ξ(F 1 +F 2 ) H +kF 2 E }d  ~ Polarized beam, unpolarized target: H( ,t) ξ=x B /(2-x B ) Unpolarized beam, longitudinal target:  UL ~ sin  {F 1 H +ξ(F 1 +F 2 )( H +ξ/(1+ξ) E) }d  ~ H( ,t) ~ Cleanest process: Deeply Virtual Compton Scattering

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

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

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

21 DVCS beam asymmetry at 12 GeVCLAS12 ep ep  High luminosity and large acceptance allows wide coverage in Q 2 < 8 GeV 2, x B < 0.65, and t< 1.5GeV 2 Experimental DVCS program E was approved for the 12 GeV upgrade using polarized beam and polarized targets. sinφ moment of A LU

22 Separate Sivers and Collins effects Sivers angle, effect in distribution function: –(  h -  s ) = angle of hadron relative to initial quark spin Collins angle, effect in fragmentation function: –(  h +  s ) =  +(  h -  s’ ) = angle of hadron relative to final quark spin e-e’ plane q Scattering Plane target angle hadron angle

23 Access TMDs through Semi-Inclusive DIS Unpolarized Polarized Target Polarized Beam and Target Boer-Mulder Sivers Transversity Pretzelosity f 1 = f 1T  = g 1 = g 1T  = h1 =h1 = h 1L  = h 1T  = h 1T = S L, S T : Target Polarization; e : Beam Polarization

24 Access TMDs through Semi-Inclusive DIS

25 Transverse Momentum Dependent Parton Distributions (TMDs) f 1T  = f 1 = g 1 = g 1T  = h 1L  = h1 =h1 = h 1T = h 1T  = Transversity Boer-Mulder Pretzelosity Sivers Helicity Nucleon Spin Quark Spin Leading Twist

26 A Solenoid Spectrometer for SIDIS SIDIS SSAs depend on 4 variables (x, Q 2, z and P T ) Large angular coverage and precision measurement of asymmetries in 4-D phase space are essential.

27 SoLID Transversity Projected Data Total 1400 bins in x, Q 2, P T and z for 11/8.8 GeV beam. z ranges from 0.3 ~ 0.7, only one z and Q 2 bin of 11/8.8 GeV is shown here. π + projections are shown, similar to the π -.

28 TopicHall AHall BHall CHall DTotal The Hadron spectra as probes of QCD (rated) (GluEx and heavy baryon and meson spectroscopy) The transverse structure of the hadrons (rated) (Elastic and transition Form Factors)423 9 The longitudinal structure of the hadrons (rated) (Unpolarized and polarized parton distribution functions)224 8 The 3D structure of the hadrons (unrated) (Generalized Parton Distributions and Transverse Momentum Distributions) Hadrons and cold nuclear matter (rated) (Medium modification of the nucleons, quark hadronization, N-N correlations, hypernuclear spectroscopy, few-body experiments)125 8 Low-energy tests of the Standard Model and Fundamental Symmetries (rated at PAC 37)2 1 3 TOTAL GeV Approved Experiments by Physics Topics

29 TopicHall AHall BHall CHall DTotal The Hadron spectra as probes of QCD (rated) (GluEx and heavy baryon and meson spectroscopy) The transverse structure of the hadrons (rated) (Elastic and transition Form Factors) The longitudinal structure of the hadrons (rated) (Unpolarized and polarized parton distribution functions) The 3D structure of the hadrons (unrated) (Generalized Parton Distributions and Transverse Momentum Distributions) Hadrons and cold nuclear matter (rated) (Medium modification of the nucleons, quark hadronization, N-N correlations, hypernuclear spectroscopy, few-body experiments) Low-energy tests of the Standard Model and Fundamental Symmetries (to be rated at PAC 37) TOTAL Days in red are the requested days to be reviewed at PAC38 12 GeV Approved Experiments by PAC Days

30 Electron Ion Collider 30 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 GeV ep/eA collider fully-polarized, longitudinal and transverse luminosity: up to few x e-nucleons cm -2 s -1 Upgradable to higher energies (250 GeV protons)

31 EIC Physics Overview GeV 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 12 GeV we study mostly the valence quark component, which can be described with methods of nuclear physics (fixed number of particles). 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 (Q 2 ) dependence. mEIC EIC

32 Medium Energy 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 cold ring warm 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 (Challenge to accelerator physics!)

37 SIDIS SSA at EIC GeV 3+20 GeV 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 e + A facilities For 1 km MEIC ring

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

43 EIC Realization Imagined Activity Name Gev Upgrade FRIB EIC Physics Case NSAC LRP EIC CD0 EIC Machine Design/R&D EIC CD1/Downsel EIC CD2/CD3 EIC Construction

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