1. The 12 GeV Upgrade of Jefferson Lab: Physics Program and Project Status Will Brooks Jefferson Lab

2. Jefferson Lab Today 2000 member international user community engaged in exploring quark- gluon structure of matter A C Superconducting accelerator provides 100% duty factor beams of unprecedented quality, with energies up to 6 GeV. CEBAF’s innovative design allows delivery of beam with unique properties to three experimental halls simultaneously Each of the three halls offers complementary experimental capabilities and allows for large equipment installations to extend scientific reach. B

3. A B C Jefferson Lab Today Two high-resolution 4 GeV spectrometers Large acceptance spectrometer electron/photon beams 7 GeV spectrometer, 1.8 GeV spectrometer, large installation experiments Hall A Hall B Hall C

4. Jefferson Lab Tomorrow Double the beam energy to 12 GeV New large acceptance spectrometer for photon- beam physics (D) New focusing spectrometer for highest energies (C) Ten-fold increase in luminosity for large- acceptance electron beam experiments (B) New Hall Enhanced capabilities in existing Halls

5. New Capabilities in Halls A, B, & C, and a New Hall D 9 GeV tagged polarized photons and a 4  hermetic detector D Super High Momentum Spectrometer (SHMS) at high luminosity and forward angles C CLAS upgraded to higher luminosity (10 35 /cm 2 -s) B High Resolution Spectrometer (HRS) Pair, and specialized large installation experiments A

6. Highlights of the 12 GeV Science Program

7. Unlocking the secrets of QCD: confinement and space-time dynamics New and revolutionary access to the structure of the proton and neutron Discovering the quark structure of nuclei Precision tests of the Standard Model

8. Unlocking the secrets of QCD: confinement and space-time dynamics

9. The search for exotic mesons: GlueX in Hall D Excitation of the gluonic field binding the quarks in a meson is an expected consequence of the non-Abelian nature of QCD An experimental manifestation of such an excitation is ‘exotic’ quantum numbers: The focus of the GlueX experiment in Hall D is to identify and study exotic mesons, and to infer features of confinement from the observed spectrum

10. Lattice QCD studies confirm flux tube formation for quenched static quarks Resulting effective potential is approximately linear with positive slope Light quarks may be more complicated but qualitative features are expected to remain, resulting in an excitation spectrum

11. Exotics expected in a mass range well-matched to GlueX detector and 12 GeV electron beam Linearly polarized photons of 9 GeV give access to this mass range and offer several advantages relative to pion beam searches Mapping out the full nonet of exotic mesons is planned Extensive parallel effort in Lattice QCD is underway Experiment optimized for high sensitivity to exotics

12. Quark Propagation and Hadron Formation: QCD Confinement in Forming Systems How long can a light quark remain deconfined? –The production time  p measures this –Deconfined quarks emit gluons –Measure  p via medium-stimulated gluon emission How long does it take to form the color field of a hadron? –The formation time  f h measures this –Hadrons interact strongly with nuclear medium –Measure  f h via hadron attenuation in nuclei

13. How long can a light quark remain deconfined? Ubiquitous sketch of hadronization process: string/color flux tube RG GY Dominant mechanism not known from experiment Kopeliovich, Nemchik, Predazzi, Hayashigaki, Nuclear Physics A 740 (2004) 211–245

14. Two distinct dynamical stages, each with characteristic time scale: Formation time t f h Production time t p Time during which quark is deconfined Signaled by medium-stimulated energy loss via gluon emission: (p T broading) Time required to form color field of hadron Signaled by interactions with known hadron cross sections No gluon emission (Hadron attenuation) These time scales are essentially unknown experimentally Accardi, Grünewald, Muccifora, Pirner, Nuclear Physics A 761 (2005) 67–91

15. Experimental Approach Direct measurements of time intervals at femptometer distance scales are feasible using nuclei as spatial analyzers The well-understood properties of nuclei (densities, currents) make a reliable analysis feasible With an assortment of nuclei of varying size, a systematic study can be performed Airapetian, et al. (HERMES) PRL 96, 162301 (2006) Two observables: 1.p T broadening 2.Hadronic multiplicity ratio

16. Production length from JLab/CLAS 5 GeV data (Kopeliovich, Nemchik, Schmidt, hep-ph/0608044)

17. Accessible Hadrons (12 GeV) Formation length extraction For more on this, see talk by W. B. on Friday morning

18. Color transparency in  electroproduction Color Transparency is a spectacular prediction of QCD: under the right conditions, nuclear matter will allow the transmission of hadrons with reduced attenuation Totally unexpected in an hadronic picture of strongly interacting matter, but straightforward in quark gluon basis Why rho? Should be evident first in mesons

19. The signature of CT is the rising of the nuclear transparency TA with increasing hardness of the reaction (Q) Measurement at fixed coherence length needed for unambiguous interpretation

20. Predicted results high- precision, will permit systematic studies For more on this, see talk by K. Hafidi on Friday morning

21. New and revolutionary access to the structure of the proton and neutron

22. Valence d-quark distributions poorly known

23. Valence structure function flavor dependence

24. Valence spin structure

25. Important complement to RHIC Spin data

26. Proton electric form factor

27. Neutron Magnetic Form Factor

28. Generalized Parton Distributions

29. GPDs via cross sections and asymmetries

30. New, comprehensive view of hadronic structure

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

32. The quark structure of nuclei

33. The 12 GeV Program for the Physics of Nuclei Quark propagation through nuclei Color transparency GPDs of nuclei Universal scaling behavior Threshold J/  photoproduction on nuclei Short-range correlations and cold dense matter Few-body form factors The quark structure of nuclei

34. Nucleons and Pions or Quarks and Gluons? From a field theoretic perspective, nuclei are a separate solution of QCD Lagrangian –Not a simple convolution of free nucleon structure with Fermi motion ‘Point nucleons moving non-relativistically in a mean field’ describes lowest energy states of light nuclei very well –But description must fail at small distances In nuclear deep-inelastic scattering, we look directly at the quark structure of nuclei This is new science, and largely unexplored territory New experimental capabilities to attack long-standing physics issues

35. The QCD Lagrangian and Nuclear “Medium Modifications” Leinweber, Signal et al. The QCD vacuum Long-distance gluonic fluctuations Lattice calculation demonstrates reduction of chiral condensate of QCD vacuum in presence of hadronic matter

36. Does the quark structure of a nucleon get modified by the suppressed QCD vacuum fluctuations in a nucleus?

37. Observation that structure functions are altered in nuclei stunned much of the HEP community 23 years ago ~1000 papers on the topic; the best models explain the curve by change of nucleon structure, BUT more data are needed to uniquely identify the origin What is it that alters the quark momentum in the nucleus? Quark Structure of Nuclei: Origin of the EMC Effect J. Ashman et al., Z. Phys. C57, 211 (1993) J. Gomez et al., Phys. Rev. D49, 4348 (1994) x JLab 12

38. Unpacking the EMC effect With 12 GeV, we have a variety of tools to unravel the EMC effect: –Parton model ideas are valid over fairly wide kinematic range –High luminosity –High polarization New experiments, including several major programs: – Precision study of A-dependence; x>1; valence vs. sea – g 1A (x) “Polarized EMC effect” – influence of nucleus on spin – Flavor-tagged polarized structure functions  u A (x A ) and  d A (x A ) – x dependence of axial-vector current in nuclei (can study via parity violation) – Nucleon-tagged structure functions from 2 H and 3 He with recoil detector – Study x-dependence of exclusive channels on light nuclei, sum up to EMC

39. EMC Effect - Theoretical Explanations Quark picture Multi-quark cluster models –Nucleus contains multinucleon clusters (e.g., 6-quark bag) Dynamical rescaling –Confinement radius larger due to proximity to other nucleons Hadron picture Nuclear binding –Effects due to Fermi motion and nuclear binding energy, including virtual pion exchange Short range correlations –High momentum components in nucleon wave function

40. What is the role of binding energy in the EMC effect? What is the role of Fermi momentum (at high x)? Are virtual pions important?

41. EMC Effect in 3 He and 4 He  Current data do not differentiate between A-dependence or  -dependence.  Can do exact few-body calculations, and high-precision measurement  Fill in high-x region – transition from rescaling to Fermi motion? SLAC fit to heavy nuclei (scaled to 3 He) Calculations by Pandharipande and Benhar for 3 He and 4 He Approximate uncertainties for 12 GeV coverage Hermes data

42. Do multi-quark clusters exist in the nuclear wavefunction? Do they contribute significantly to the EMC effect? How to answer: tag overlapping nucleons…

43. 12 GeV gives access to the high- x, high-Q 2 kinematics needed to find multi-quark clusters Correlated nucleon pair Six-quark bag (4.5% of wave function) Fe(e,e’) 5 PAC days Multi-quark clusters are accessible at large x (>>1) and high Q 2 Mean field

44. Is the EMC effect a valence quark phenomenon, or are sea quarks also involved? Drell-Yan data from Fermilab, showing no clear excess of anti-quarks in nuclei Incident quark, x 1 Target anti-quark, x 2 ++ --

45. 0.5 1.0 gluons sea valence 0.1 1.0 S. Kumano, “Nuclear Modification of Structure Functions in Lepton Scattering,” hep-ph/0307105 JLab 12 Sea and valence expected to be quite different Detect  +,  -, (K +, K - ), do flavor decomposition x Flavor-tagged EMC Effect  Global fit of electron and muon DIS experiments and Drell-Yan data

46. What is the role of relativity in the description of the EMC effect? What can be learned from spin? Quantum field theory for nuclei: – Large (300-400 MeV) Lorentz scalar and vector fields required – Binding energies arise from cancellations of these large fields – Relativity an essential component Quark-Meson Coupling model: – Lower Dirac component of confined light quark modified most by the scalar field How to probe the lower component further? SPIN! Surprises: 23 years ago – EMC effect 17 years ago – the ‘spin crisis’ will there be another ‘spin crisis’ in nuclei?

47. g 1A (x) – “Polarized EMC Effect” Spin-dependent parton distribution functions for nuclei essentially unknown Can take advantage of modern technology for polarized solid targets to perform systematic studies – Dynamic Nuclear Polarization Correct relativistic description will also help to explain ordinary EMC effect

48. g 1 (A) – “Polarized EMC Effect” – Some Solid Target Possibilities NuclideCompoundPolarization (%) 6 Li 6 LiD45 7 Li 7 LiD90 11 BC 2 N 2 BH 13 75 13 C 13 C 4 H 9 OH65 19 FLiF90 Proton embedded in 7 Li with over 50% polarization!

49. Polarized EMC Effect Assumes 11 GeV beam, 40% target polarization, 80% beam polarization and running for 70 days; study by Vipuli Dharmawardane Systematic error target is < 5%

50. Can we go further in understanding relativistic effects and the role of quark flavor? How much of the spin is carried by the valence quarks? Is there a nuclear ‘spin crisis’ too?

51. “Polarized EMC Effect” – Flavor Tagging Can perform semi-inclusive DIS on sequence of polarized targets, measuring  + and  -, decompose to extract  u A (x A ),  d A (x A ). Challenging measurement, but have new tools: –High polarization for a wide variety of targets –Large acceptance detectors to constrain systematic errors and tune models  u A (x A )  u(x) x  u v (x) free nucleon + scalar field + Fermi + vector field (total)  d v (x) W. Bentz, I. Cloet, A. W. Thomas Ratios  u A (x A )  u(x) nuclear matter

52. Precision Tests of the Standard Model

53. Electron-Quark Phenomenology C 1u and C 1d will be determined to high precision by APV and Qweak C 2u and C 2d are small and poorly known: can be accessed in PV DIS New physics such as compositeness, new gauge bosons: Deviations in C 2u and C 2d might be fractionally large A V V A Proposed JLab upgrade experiment will improve knowledge of 2C 2u -C 2d by more than a factor of 20

54. Parity Violating Electron DIS f i (x) are quark distribution functions e-e- N X e-e- Z*Z* ** For an isoscalar target like 2 H, structure functions largely cancels in the ratio: Provided Q 2 and W 2 are high enough and x ~ 0.3 Must measure APV to fractional accuracy better than 1% 11 GeV at high luminosity makes very high precision feasible JLab is uniquely capable of providing beam of extraordinary stability Control of systematics being developed at 6 GeV

55. 2 H Experiment at 11 GeV E’: 6.8 GeV ± 10%  lab = 12.5 o A PV = 290 ppm I beam = 90 µA 800 hours  (A PV )=1.0 ppm 60 cm LD 2 target 1 MHz DIS rate, π/e ~ 1 HMS+SHMS x Bj ~ 0.45 Q 2 ~ 3.5 GeV 2 W 2 ~ 5.23 GeV 2  (2C 2u -C 2d )=0.01 PDG: -0.08 ± 0.24 Theory: +0.0986

56. The 12 GeV Upgrade Project: Status and Schedule

57. DOE Generic Project Timeline We are here DOE Reviews

58.  2004-2005 Conceptual Design (CDR) - finished  2004-2008 Research and Development (R&D) - ongoing  2006 Advanced Conceptual Design (ACD) - finished  2006-2009 Project Engineering & Design (PED) - starting  2009-2013 Construction – starts in less than two years!  Accelerator shutdown start early 2012  Accelerator commissioning late 2012 - early 2013  2013-2014 Pre-Ops (beam commissioning)  Hall commissioning start early-mid 2013 (based on funding profile provided April 2006) 12 GeV Upgrade: Phases and Schedule

59. June - DOE Annual Review of Project Progress –High marks for progress and planning July – 35% Design and Safety Review for Hall D Complex Civil Construction, plus completed a value engineering study August - JLab PAC 30 –First review of 12 GeV proposals – “commissioning experiments” –Key first step in identifying the research interests and significant contributions of international and other non-DOE collaborators September – Two Internal Project Reviews: 1) Cryomodules and 2) new Superconducting Magnets October – Start of FY07, $7M of PED funds now flowing; A&E firm authorized to proceed with 60% design of Hall D Complex; project design phase now in full swing! 12 GeV Upgrade: Recent News

60. 12 GeV Physics Plans for FY07 Detailed plans for FY07 R&D and PED have been cast into a resource-loaded schedule –250 activities and milestones –Approximately 25 paid FTE’s matrixed from ~50 laboratory staff –Additional 17 FTE’s of contributed university labor –Incorporates ESH&Q activities and milestones Major R&D goals include: –Prototyping of 8 detector systems –Three studies focusing on superconducting magnets –Six studies on electronics, detector, or shielding issues Major PED efforts include: –Reference designs for 7 superconducting magnets + Tagger system –Designs for 12 major detector systems –Designs for electronics and infrastructure components

61. FY07 DOE Reviews  Early January (tentative): “Project Status Review”  4-person review committee, led by JSO  Focus: Resource-loaded schedule, extensive documentation  Late January: “Mini-Review”  Lehman/DOE-NP review, small group  Early Summer: Baseline Readiness Review, stage I  Conducted by Lehman office (IPR). Major review.  Mid-Summer: Baseline Readiness Review, stage II  Conducted by OECM (EIR). Major review.

62. Conclusions  Exciting science program!  Amazingly broad and diverse  Earthshaking impacts  Project is now in intensive design phase  Construction phase less than 2 years away  Goal is to bring all systems to readiness for baseline in 6 months  We are on track for accomplishing this!

63. BACKUP TRANSPARENCIES

67. Reminder: semi-inclusive DIS Cross section ~ Detect a final state hadron in addition to scattered electron Can ‘tag’ the flavor of the struck quark by measuring the hadrons produced: ‘flavor tagging’

68. g 1 (A) – “Polarized EMC Effect” – 7 Li as Target Shell model: 1 unpaired proton, 2 paired neutrons in P 3/2, closed S 1/2 shell. Cluster model: triton + alpha 7 Li polarization: 90% Nucleon polarization calculations: Cluster model: 57% GFMC: 59% 59% x 90% = 53% Proton embedded in 7 Li with over 50% polarization! S 1/2 P 3/2