1. The Frontiers of Nuclear Science: from 12 GeV to EIC Rolf Ent INT10-03 Program, Institute for Nuclear Theory, Seattle, WA Workshop on “The Science Case for an EIC”, November 16-19, 2010 A personal perspective on the 12-GeV and EIC science The 12-GeV Upgrade -The 12 GeV science (relevant to an EIC) Highlights & Shortcomings -The 12 GeV Roadmap The Electron-Ion Collider - The EIC science - The EIC Roadmap Conclusions

2. NSAC 2007 Long Range Plan Recommendation I “We recommend completion of the 12 GeV Upgrade at Jefferson Lab. The Upgrade will enable new insights into the structure of the nucleon, the transition between the hadronic and quark/gluon descriptions of nuclei, and the nature of confinement.” A fundamental challenge for modern nuclear physics is to understand the structure and interactions of nucleons and nuclei in terms of QCD. Doubling the energy of the JLAB accelerator will enable three-dimensional imaging of the nucleon, revealing hidden aspects of the internal dynamics.

3. Highlights of the 12 GeV Science Program Unlocking the secrets of QCD: quark confinement New and revolutionary access to the structure of the proton and neutron Discovering the quark structure of nuclei High precision tests of the Standard Model Items in blue related to

4. Measuring High-x Structure Functions REQUIRES: High beam polarization High electron current High target polarization Large solid angle spectrometers 12 GeV will access the regime (x > 0.3), where valence quarks dominate d/u Also with 3 H/ 3 He and EW

5. Beyond form factors and quark distributions – Generalized Parton Distributions (GPDs) Proton form factors, transverse charge & current densities Structure functions, quark longitudinal momentum & helicity distributions X. Ji, D. Mueller, A. Radyushkin (1994-1997) Correlated quark momentum and helicity distributions in transverse space - GPDs Extend longitudinal quark momentum & helicity distributions to transverse momentum distributions - TMDs 2000’s

6. The path towards the extraction of GPDs A =           = Use polarization!  LU ~ sin  Im{F 1 H +  }d   = x B /(2-x B ) H( ,t) Kinematically suppressed e p ep  Subset of projected results

7. Projected results Spatial Image Projected precision in extraction of GPD H at x =  Rich program in DVCS in valence quark region

8. Deep Exclusive Meson Production @ 12 GeV Measurements at DESY of diffractive channels (J/ , , ,  ) confirm the applicability of QCD factorization: t-slopes universal at high Q 2 flavor relations  :  Fit with d  /dt = e -Bt Pseudoscalar (and vector) meson production at 12 GeV: typically up to Q 2 = 10 GeV 2  Experimental QCD factorization tests of (e,e’  + ) and (e,e’K + ) essential B (GeV -2 )

9. Valence Quark Structure and Parton Distributions Access to valence quark region through DIS at large x will be augmented with a SIDIS program Boer-Mulders asymmetry for pions as function of Q 2 and p T

10. Closed (open) symbols reflect data after (before) events from coherent  production are subtracted GRV & CTEQ, @ LO or NLO (Note: z = 0.65 ~ M x 2 = 2.5 GeV 2 ) Onset of the Parton Model in SIDIS @ JLab Good description for p and d targets for 0.4 < z < 0.65 1 H, 2 H(e,e’  +/- )X factorization  e q 2 q(x) D q  (z) 6 GeV: z > 0.4

11. 12-GeV: study x-z Factorization for kaons P.J. Mulders, hep-ph/0010199 (EPIC Workshop, MIT, 2000) At large z-values easier to separate current and target fragmentation region  for fast hadrons factorization (Berger Criterion) “works” at lower energies At W = 2.5 GeV: z > 0.6 If same arguments as validated for  apply to K: (but, z < 0.65 limit may not apply for kaons!) Access to sea/strange quarks not clear with 12 GeV

12. R =  L /  T in (e,e’  ) SIDIS  quark Knowledge on R =  L /  T in SIDIS is essentially non-existing! If integrated over z (and p T, , hadrons), R SIDIS = R DIS R SIDIS may vary with z At large z, there are known contributions from exclusive and diffractive channels: e.g., pions from  and    +  - R SIDIS may vary with transverse momentum p T Is R SIDIS  + = R SIDIS  - ? Is R SIDIS H = R SIDIS D ? Is R SIDIS K + = R SIDIS  + ? Is R SIDIS K + = R SIDIS K - ? We measure kaons too! (with about 10% of pion statistics) R SIDIS = R DIS test of dominance of quark fragmentation  e q 2 q(x) D q  (z) “A skeleton in our closet”

13. R DIS R DIS (Q 2 = 2 GeV 2 ) Cornell data of 70’s R =  L /  T in SIDIS (ep  e’  X) Cornell data conclusion: “data both consistent with R = 0 and R = R DIS ” Some hint of large R at large z in Cornell data? JLab@12: scans vs. Q 2 /x, z (Q 2 = 2& 4) & P T

14. Transverse Momentum Dependence of Semi-Inclusive Pion Production Not much is known about the orbital motion of partons Significant net orbital angular momentum of valence quarks implies significant transverse momentum of quarks P t = p t + z k t + O(k t 2 /Q 2 ) Final transverse momentum of the detected pion P t arises from convolution of the struck quark transverse momentum k t with the transverse momentum generated during the fragmentation p t. z = E  / p T ~  < 0.5 GeV optimal for studies as theoretical framework for Semi-Inclusive Deep Inelastic Scattering has been well developed at small transverse momentum [A. Bacchetta et al., JHEP 0702 (2007) 093].

15. Unpolarized SIDIS – JLab @ 6 GeV Constrain k T dependence of up and down quarks separately 1) Probe  + and  - final states 2) Use both proton and neutron (d) targets 3) Combination allows, in principle, separation of quark width from fragmentation widths (if sea quark contributions small) 1 st example: Hall C, PL B665 (2008) 20 Simple model, host of assumptions (factorization valid, fragmentation functions do not depend on quark flavor, transverse momentum widths of quark and fragmentation functions are gaussian and can be added in quadrature, sea quarks are negligible, assume Cahn effect, etc.)  Example (favored) (up) Example x = 0.32 z = 0.55 12 GeV: start testing assumptions!

16. Does the quark structure of a nucleon get modified by the suppressed QCD vacuum fluctuations in a nucleus? 1)Measure the EMC effect on the mirror nuclei 3 H and 3 He 2)Is the EMC effect a valence quark only effect? 3)Is the spin-dependent EMC effect larger? 4)Can we reconstruct the EMC effect on 3 He and 4 He from all measured reaction channels? 5)Is there any signature for 6-quark clusters? 6)Can we map the effect vs. transverse momentum/size? Reminder: EMC effect is effect that quark momenta in nuclei are altered 12 GeV is probably our best chance to understand the origin of the EMC effect in the valence quark region

17. Using the nuclear arena How long can an energetic quark remain deconfined? How long does it take a confined quark to form a hadron? Formation time t f h Production time t p Quark is deconfined Hadron is formed Hadron attenuation CLAS Time required to produce colorless “pre- hadron”, signaled by medium-stimulated energy loss via gluon emission Time required to produce fully- developed hadron, signaled by CT and/or usual hadronic interactions

18. Transverse Momentum Broadening  p T 2 reaches a “plateau” for sufficiently large quark energy, for each nucleus (L is fixed), related to production length (start seeing this effect in 6-GeV data). pT2pT2 Projected Data

19. Solid 19 Sensitivity: C 1 and C 2 Plots after 12 GeV Cs 12 GeV PVDIS Qweak 12 GeV PVDIS World’s data Precision Data (w. Qweak, 6 GeV/PVDIS, 12 GeV/PVDIS) Gain factor of 80 or so in C 2 combination with 12 GeV! 6 GeV (Vector quark and axial- vector quark couplings)

20. N  ee ~ 25 TeV JLab Møller LHC New Contact Interactions Møller Parity-Violating Experiment: New Physics Reach (example of large installation experiment with 11 GeV beam energy) A FB (b) measures product of e- and b-Z couplings A LR (had) measures purely the e-Z couplings Proposed A PV (b) measures purely the e-Z couplings at a different energy scale Not “just another measurement” of sin 2 (  w )

21.  2004-2005 Conceptual Design (CDR) - finished  2004-2008 Research and Development (R&D) - finished  2006 Advanced Conceptual Design (ACD) - finished  2006-2009 Project Engineering & Design (PED) - finished  2009-2014 Construction – in second year of construction  Parasitic machine shutdown May 2011 through Oct. 2011  Accelerator shutdown start mid-May 2012  Accelerator commissioning start mid-May 2013  2013-2015 Pre-Ops (beam commissioning)  Hall A commissioning start October 2013  Hall D commissioning start April 2014  Halls B and C commissioning start October 2014 12 GeV Upgrade: Phases and Schedule Timescale (for 310M$ project): over 10 years – after numbered recommendation

22. Highlights (& Shortcomings) of the 12 GeV Science Program New and revolutionary access to the structure of the proton and neutron -Form factors to high Q 2 (about 10 GeV 2 ) -Large x PDFs, DVCS & TMD measurements for x > 0.1 -No strange/sea quarks, probing  /  /K production Discovering the quark structure of nuclei -Disentangle the origin of the (valence) EMC effect -Establish Color Transparency for meson production -No target fragmentation, limited hadronization studies High precision tests of the Standard Model - Probably as good as anyone can do in EW at E < M z

23. Nuclear Physics – 12 GeV to EIC The role of Gluons and Sea Quarks Study the Force Carriers of QCD

24. A High-Luminosity Electron Ion Collider Base EIC Requirements: range in energies from s = few 100 to s = few 1000 & variable fully-polarized (>70%), longitudinal and transverse ion species up to A = 200 or so high luminosity: about 10 34 e-nucleons cm -2 s -1 upgradable to higher energies 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.”

25. Why an Electron-Ion Collider? Longitudinal and Transverse Spin Physics! - 70+% polarization of beam and target without dilution - transverse polarization also 70%! Detection of fragments far easier in collider environment! - fixed-target experiments boosted to forward hemisphere - no fixed-target material to stop target fragments - access to neutron structure w. deuteron beams (@ p m = 0!) Easier road to do physics at high CM energies! - E cm 2 = s = 4E 1 E 2 for colliders, vs. s = 2ME for fixed-target  4 GeV electrons on 12 GeV protons ~ 100 GeV fixed-target - Easier to produce many J/  ’s, high-p T pairs, etc. - Easier to establish good beam quality in collider mode Targetf dilution, fixed_target P fixed_target f 2 P 2 fixed_target f 2 P 2 EIC p0.20.80.030.5 d0.40.50.040.5 Longitudinal polarization FOM

26. longitudinal momentum transverse distribution orbital motion quark to hadron conversion Dynamical structure! Gluon saturation? Obtain detailed differential transverse quark and gluon images (derived directly from the t dependence with good t resolution!) - Gluon size from J/  and  electroproduction - Singlet quark size from deeply virtual compton scattering (DVCS) - Strange and non-strange (sea) quark size from  and K production Determine the spin-flavor decomposition of the light-quark sea Constrain the orbital motions of quarks & anti-quarks of different flavor - The difference between  +,  –, and K + asymmetries reveals the orbits Map both the gluon momentum distributions of nuclei (F 2 & F L measurements) and the transverse spatial distributions of gluons on nuclei (coherent DVCS & J/  production). At high gluon density, the recombination of gluons should compete with gluon splitting, rendering gluon saturation. Can we reach such state of saturation? Explore the interaction of color charges with matter and understand the conversion of quarks and gluons to hadrons through fragmentation and breakup. Why a New-Generation EIC? Why not HERA?

27. The Science of an (M)EIC Nuclear Science Goal: How do we understand the visible matter in our universe in terms of the fundamental quarks and gluons of QCD? Overarching EIC Goal: Explore and Understand QCD Three Major Science Questions for an EIC (from NSAC LRP07): 1)What is the internal landscape of the nucleons? 2)What is the role of gluons and gluon self-interactions in nucleons and nuclei? 3)What governs the transition of quarks and gluons into pions and nucleons? Or, Elevator-Talk EIC science goals: Map the spin and spatial structure of quarks and gluons in nucleons (show the nucleon structure picture of the day…) Discover the collective effects of gluons in atomic nuclei (without gluons there are no protons, no neutrons, no atomic nuclei) Understand the emergence of hadronic matter from quarks and gluons (how does E = Mc 2 work to create pions and nucleons?) + Hunting for the unseen forces of the universe?

28. The Science of an (M)EIC Or, Elevator-Talk EIC science goals: Map the spin and spatial structure of quarks and gluons in nucleons (show the nucleon structure picture of the day…) Discover the collective effects of gluons in atomic nuclei (without gluons there are no protons, no neutrons, no atomic nuclei) Understand the emergence of hadronic matter from quarks and gluons (how does E = Mc 2 work to create pions and nucleons?) + Hunting for the unseen forces of the universe?

29. Similar reduction with neural networks (Rojo + Accardi) F2p & F2d @ high x still needed from EIC s = 1000 One year of running (26 weeks) at 50% efficiency, or 35 fb -1 F2F2 Q 2 (GeV 2 ) Similar improvement in F 2 p at large x F 2 n tagging measurements relatively straightforward in EIC designs EIC will have excellent kinematics to further measure/constrain n/p at large x! Sensible reduction in PDF error, likely larger reduction if also energy scan

30. Projected g 1 p Landscape of the EIC RHIC-Spin Similar for g 2 p (and g 2 n )! Access to  g/g is possible from the g 1 p measurements through the QCD evolution, or from open charm (D 0 ) production (see below), or from di- jet measurements.

32. 100 days, L =10 33, s = 1000 Sea Quark Polarization Spin-Flavor Decomposition of the Light Quark Sea | p = + + + … > u u d u u u u d u u d d d Many models predict  u > 0,  d < 0 Access requires s ~ 1000 (and good luminosity) }

33. Transverse Quark & Gluon Imaging Deep exclusive measurements in ep/eA with an EIC: diffractive:transverse gluon imagingJ/ , ,  o,  (DVCS) non-diffractive:quark spin/flavor structure , K,  +, … Describe correlation of longitudinal momentum and transverse position of quarks/gluons  Transverse quark/gluon imaging of nucleon (“tomography”) Are gluons uniformly distributed in nuclear matter or are there small clumps of glue? Are gluons & various quark flavors similarly distributed? (some hints to the contrary)

34. Detailed differential images from nucleon’s partonic structure EIC: Gluon size from J/  and  electroproduction (Q 2 > 10 GeV 2 ) [Transverse distribution derived directly from t  dependence] t Hints from HERA: Area (q + q) > Area (g) Dynamical models predict difference: pion cloud, constituent quark picture - t EIC: singlet quark size from deeply virtual compton scattering EIC: strange and non-strange (sea) quark size from  and K production Q 2 > 10 GeV 2 for factorization Statistics hungry at high Q 2 !

35. Image the Transverse Momentum of the Quarks An EIC with high transverse polarization is the optimal tool to to study this! The difference between the  +,  –, and K + asymmetries reveals that quarks and anti-quarks of different flavor are orbiting in different ways within the proton. Swing to the left, swing to the right: A surprise of transverse-spin experiments Only a small subset of the (x,Q 2 ) landscape has been mapped here: terra incognita

36. Vanish like 1/p T (Yuan) Correlation between Transverse Spin and Momentum of Quarks in Unpolarized Target All Projected Data Perturbatively Calculable at Large p T - (Harut Avakian, Antje Bruell) Assumed 100 days of 10 35 luminosity

37. The Science of an (M)EIC Or, Elevator-Talk EIC science goals: Map the spin and spatial structure of quarks and gluons in nucleons (show the nucleon structure picture of the day…) Discover the collective effects of gluons in atomic nuclei (without gluons there are no protons, no neutrons, no atomic nuclei) Understand the emergence of hadronic matter from quarks and gluons (how does E = Mc 2 work to create pions and nucleons?) + Hunting for the unseen forces of the universe?

38. Gluons in Nuclei NOTHING!!! Large uncertainty in gluon distributions need range of Q 2 in shadowing region,  x ~ 10 -2 -10 -3  s EIC = 1000+ + Transverse distribution of gluons on nuclei from coherent Deep-Virtual Compton Scattering and coherent J/  production What do we know about gluons in a nucleus? [Measurements at DESY of diffractive channels ( J/ , , ,  ) confirmed the applicability of QCD factorization: t-slopes universal at high Q 2 & flavor relations  :  hold  Gluon radius of a nucleus? Ratio of gluons in lead to deuterium

39. E772 Drell-Yan: Is the EMC effect a valence quark phenomenon or are sea quarks involved? Sea-Quarks in Nuclei Tremendous opportunity for experimental improvements! 0.5 1.0 gluons sea valence 0.1 1.0 S. Kumano, “Nuclear Modification of Structure Functions in Lepton Scattering,” hep-ph/0307105 x R Ca  Use combination of F L A & F 2 A measurements, EW measurements, ‘flavor tagging’, etc.

40. Unresolved Questions in Nuclei x F 2 A /F 2 D F 2 structure functions, or quark distributions, are altered in nuclei ~1000 papers on the topic; the best models explain the curve by change of nucleon structure - BUT we are still learning (e.g. local density effect) – and 12 GeV optimal to attack the valence region. 12 GeV EIC: Is shadowing a leading- or higher-twist phenomenon? What is the dynamical origin of anti-shadowing?

41. The Science of an (M)EIC Or, Elevator-Talk EIC science goals: Map the spin and spatial structure of quarks and gluons in nucleons (show the nucleon structure picture of the day…) Discover the collective of gluons in atomic nuclei (without gluons there are no protons, no neutrons, no atomic nuclei) Understand the emergence of hadronic matter from quarks and gluons (how does E = Mc 2 work to create pions and nucleons?) + Hunting for the unseen forces of the universe?

42. Hadronization un-integrated parton distributions current fragmentation target fragmentation Fragmentation from QCD vacuum +  -  EIC: Understand the conversion of quarks and gluons to hadrons through fragmentation and breakup EIC: Explore the interaction of color charges with matter

43. Transverse Momentum Broadening  p T 2 reaches a “plateau” for sufficiently large quark energy, for each nucleus (L is fixed). pT2pT2 In the pQCD region, the effect is predicted to disappear (arbitrarily put at =1000)

44. Hadronization EIC: Explore the interaction of color charges with matter EIC: Understand the conversion of quarks and gluons to hadrons through fragmentation and breakup (1 month only)

45. EIC Realization From Hugh Montgomery’s presentation at the INT10-03 Program in Seattle Assumes endorsement for an EIC at the next ~2012/13 NSAC Long Range Plan

46. Summary The last decade+ has seen tremendous progress in our understanding of the partonic sub-structure of nucleons and nuclei, due to: Findings at the US nuclear physics flagship facilities: RHIC and CEBAF The surprises found at HERA (H1, ZEUS, HERMES), and now COMPASS/CERN. The development of a theory framework allowing for a revolution in our understanding of the inside of hadrons … GPDs, TMDs, Lattice QCD … hand in hand with the stellar technological advances in polarized beam and parity-quality electron beam delivery. This has led to new frontiers of nuclear science: - the possibility to truly explore and image the nucleon - the possibility to understand and build upon QCD and study the role of gluons in structure and dynamics - the unique possibility to study the interaction of color-charged objects in vacuum and matter, and their conversion to hadrons - utilizing precision electroweak studies to complement direct searches for physics beyond the Standard Model We have unique opportunities to make a (future textbook) breakthrough in nucleon structure and QCD dynamics.

47. EIC is intended to create and study gluons, which bind subatomic particles Einstein’s famous equation, E = mc 2, predicts that small amounts of mass can be transformed into large amounts of energy. Although we have demonstrated this prediction and its practical applications, the truth is that we do not yet understand how the process works – the underlying mechanisms by which mass is transformed into energy and vice versa. EIC will allow scientists to tackle this very fundamental question in physics.

48. Appendix

49. EIC@JLab High-Level Science Overview 12 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.

50. Transverse- Momentum Dependent Parton Distributions Generalized Parton Distributions u(x)  u,  u F 1 u (t) F 2 u,G A u,G P u f 1 (x) g 1, h 1 Parton Distributions Form Factors d2kTd2kT dx  = 0, t = 0 W u (x,k,r) GPD u (x, ,t) H u, E u, H u, E u ~~ p m BGPD d2kTd2kT Link to Orbital Momentum Towards a “3D” spin- flavor landscape Want P T >  but not too large! Link to Orbital Momentum p m x TMD d3rd3r TMD u (x,k T ) f 1,g 1,f 1T,g 1T h 1, h 1T, h 1L, h 1 (Wigner Function)

51. E00-108: Onset of the Parton Model (Resonances cancel (in SU(6)) in D - /D + ratio extracted from deuterium data) (Deuterium data)  quark Collinear Fragmentation factorization  e q 2 q(x) D q  (z)

52. So what about R =  L /  T for pion electroproduction?  quark “Semi-inclusive DIS” R SIDIS  R DIS disappears with Q 2 ! “Deep exclusive scattering” is the z  1 limit of this “semi-inclusive DIS” process Here, R =  L /  T ~ Q 2 (at fixed x) Have no idea at all how R will behave at large p T Example of 12-GeV projected data assuming R SIDIS = R DIS Not including a comparable systematic uncertainty: ~1.6% Planned scans in z at Q 2 = 2.0 (x = 0.2) and 4.0 GeV 2 (x = 0.4)  should settle the behavior of  L /  T for large z. Planned data cover range Q 2 = 1.5 – 5.0 GeV 2, with data for both H and D at Q 2 = 2 GeV 2  e q 2 q(x) D q  (z) Planned data cover range in P T up to ~ 1 GeV. The coverage in  is excellent (o.k.) up to P T = 0.2 (0.4) GeV.

53. Model P T dependence of SIDIS Gaussian distributions for P T dependence, no sea quarks, and leading order in (k T /q) Inverse of total width for each combination of quark flavor and fragmentation function given by: And take Cahn effect into account, with e.g. (similar for c 2, c 3, and c 4 ):

54. A V V A The couplings g depend on both electroweak physics and the weak vector and axial-vector hadronic current, and are functions of sin 2  w (g A e g V T +  g V e g A T ) Parity-Violating Asymmetries Weak Neutral Current (WNC) Interactions at Q 2 << M Z 2 Longitudinally Polarized Electron Scattering off Unpolarized Fixed Targets Mid 70sgoal was to show sin 2  w was the same as in scattering 1990-2010target couplings probe novel aspects of hadron structure Ongoingprecision measurements with carefully chosen kinematics to probe new physics at multi-TeV high energy scales

55. QCD and the Origin of Mass 99% of the proton’s mass/energy is due to the self-generating gluon field – Higgs mechanism has almost no role here. The similarity of mass between the proton and neutron arises from the fact that the gluon dynamics are the same – Quarks contribute almost nothing.

56. Gluons and QCD QCD is the fundamental theory that describes structure and interactions in nuclear matter. Without gluons there are no protons, no neutrons, and no atomic nuclei Gluons dominate the structure of the QCD vacuum Facts: –The essential features of QCD (e.g. asymptotic freedom, chiral symmetry breaking, and color confinement) are all driven by the gluons! –Unique aspect of QCD is the self interaction of the gluons –99% of mass of the visible universe arises from glue –Half of the nucleon momentum is carried by gluons

57. Where does the spin of the proton originate? (let alone other hadrons…) The Standard Model tells us that spin arises from the spins and orbital angular momentum of the quarks and gluons: ½ = ½  +  G + L Experiment:  ≈ 0.3 Gluons contribute to much of the mass and ≈ half of the momentum of the proton, but… … recent results (RHIC-Spin, COMPASS@CERN) indicate that their contribution to the proton spin is small:  G < 0.1? ( but only in small range of x…) L u, L d, L g ?

58. The Gluon Contribution to the Proton Spin at small x Superb sensitivity to  g at small x!

60. What’s the use of GPDs? 2. Describe correlations of quarks/gluons 4. Allows access to quark angular momentum (in model-dependent way) 1. Allows for a unified description of form factors and parton distributions gives transverse spatial distribution of quark (parton) with momentum fraction x Fourier transform in momentum transfer x < 0.1x ~ 0.3x ~ 0.8 3. Allows for Transverse Imaging

61. GPDs and Transverse Gluon Imaging Goal: Transverse gluon imaging of nucleon over wide range of x: 0.001 < x < 0.1 Requires: - Q 2 ~ 10-20 GeV 2 to facilitate interpretation - Wide Q 2, W 2 (x) range - luminosity of 10 33 (or more) to do differential measurements in Q 2, W 2, t Q 2 = 10 GeV 2 projected data Simultaneous data at other Q 2 -values EIC enables gluon imaging! (Andrzej Sandacz)

62. Single-Spin Asymmetry Projections with Proton 11 + 60 GeV 36 days L = 3x10 34 /cm 2 /s 2x10 -3, Q 2 <10 GeV 2 4x10 -3, Q 2 >10 GeV 2 3 + 20 GeV 36 days L = 1x10 34 /cm 2 /s 3x10 -3, Q 2 <10 GeV 2 7x10 -3, Q 2 >10 GeV 2 Polarization 80% Overall efficiency 70% z: 12 bins 0.2 - 0.8 P T : 5 bins 0-1 GeV φ h angular coverage incuded Average of Collins/Sivers/Pretzelosity projections Still with θ h <40 cut, needs to be updated (Also π - )

63. Electron-Ion Collider – Roadmap EIC (eRHIC/ELIC) webpage: http://web.mit.edu/eicc/http://web.mit.edu/eicc/ Weekly meetings at both BNL and JLab Wiki pages at http://eic.jlab.org/ & https://wiki.bnl.gov/eichttp://eic.jlab.org/ EIC Collaboration has biannual meetings since 2006 Last EIC meeting: July 29-31, 2010 @ Catholic University, DC INT10-03 program @ Institute for Nuclear Theory ongoing spin, QCD matter, imaging, electroweak Sept. 10 – Nov. 19, 2010 Periodic EIC Advisory Committee meetings (convened by BNL & JLab) After INT10-03 program (2011 – next LRP) need to produce single, community-wide White Paper laying out full EIC science program in broad, compelling strokes and need to adjust EIC designs to be conform accepted energy- luminosity profile of highest nuclear science impact followed by an apples-to-apples bottom-up cost estimate comparison for competing designs, folding in risk factors and folding in input from ongoing Accelerator R&D, EICAC and community