6 GeV Program Overview Rolf Ent PAC38 Meeting August 22 nd 2011 HallPhysics Began Experiments Completed (full/partial) Experiments Completed (equivalent C10/9537 / A 5/9762 / B11/9775 / TotalsToday174 / TotalsPAC37168 /

Good FY11 Operations Did run as promised until May 13, 2011 & started 6 Month Shut Down work Cumulative delivered beam used:Hall A 101%(routine running) Hall B 70%(HDIce delay) Hall C 82%(Qweak catching up)

Ongoing 6 GeV Program Issues remaining: Completion of g2p/GEp apparatus in Hall A Proof of polarized HDIce operations in Hall B Sufficient beam in Hall C

Year (Expt. #) ExperimentMajor Installation TasksSpecial Accel. Requirements Scientific Rating PAC Days FY2010 E05-109HAPPEx-IIICompletionSmall helicity correlations (~ 1/20*HAPPEX I) A-Complete E08-011DIS-parityHigh-speed DAQA-32 E06-002PREx: Lead ParityRoom-temperature septa Møller and Compton upgrade Small helicity correlations (~ 1/20*HAPPEX I) A30 E E DVCS on the proton and neutron PbF 2 calorimeterA, B + 40 FY2011 E E DVCS on the proton and neutron CompletionA, B+40 E08-008Deuteron electrodisintegration near threshold BigBiteB+ (C3)18 E N-  Coulomb quadrupole amplitude at low Q 2 B+3 E07-006Short Range Correlations via (e,e’pN) BigBiteA-23 E He Nuclei Response Functions C30.5 E08-014Three-nucleon correlations (x>2) A-12 Accelerator Down for 12 GeV Work Now Underway Not shown on the FY2010 Schedule is the APEX test run; it took place just after PREx Hall A: Ongoing 6 GeV Program

Page 5 Lead ( 208 Pb) Radius Experiment : PREX Elastic Scattering Parity-Violating Asymmetry Z 0 : Clean Probe Couples Mainly to Neutrons Applications : Nuclear Physics, Neutron Stars, Atomic Parity, Heavy Ion Collisions The Lead ( 208 Pb) Radius Experiment (PREX) finds neutron radius larger than proton radius by fm (+0.15, -0.17). This result provides model-independent confirmation of the existence of a neutron skin relevant for neutron star calculations. Follow-up experiment to reduce uncertainties by factor of 3 and pin down symmetry energy in EOS. A neutron skin of 0.2 fm or more has implications for our understanding of neutron stars and their ultimate fate Relativistic mean field Nonrelativistic skyrme PREX

Page 6 HAPPEx-III results final, publication in preparation -accurate measurement at Q 2 = 0.6 GeV 2, completing the parity-violating program constraining the contributions of strange quarks to the proton’s charge & magnetization. -contributions to these distributions are found to be minimal. -strange quarks do not play a substantial role in the long-range electromagnetic structure of nucleons Strangeness Contribution to Nucleon Form Factors Completes Performance Measure HP4 Pink line represents 2% of the proton form factors (in the same combination of electric and magnetic as the strange form factors)  strange quarks represent less than 2% of the proton form factors.

Page 7 Searches for a gauge boson A’ – APEX Test Run Result Future searches for a new force carrier: - APEX – electron-nucleus fixed-target, an e + e - pair in two focusing spectrometers - HPS – same, the e + e -,    - pairs in a custom Si-tracker magnetic spectrometer - DarkLight – an internal target with an electron beam in Jefferson Lab ERL, detect an e + e - pair and e’p - VEPP3 – a positron beam incident on an internal H 2 target, missing mass in (e + e -,  X) - MAMI – APEX type scheme with lower beam energy Electroproduction of A’ decay Published results : - Beam dump searches: SLAC:E137, 141; FNAL: E774 - electron and muon (g-2), limits - BaBar,  (3s)->  and     (inferred limit) - KLOE, mass of an e + e - pair (bump search) - APEX test run, mass of e + e - pair – arXiv: MAMI – APEX type scheme

Year (Expt. #) ExperimentMajor Installation TasksSpecial Accel. Requirements Scientific Rating PAC Days FY2012 Accelerator Down for 12 GeV work E08-027g 2 p and the LT Spin polarizability Septa + beamline chicane Polarized target A-24 E08-007G E p at low Q 2 A-14 E08-027g 2 p and the LT Spin polarizability CompletionA-24 E07-012Hypernuclear 16 O and production SeptaB+12 Last piece of incremental equipment funding provided by DOE/NP Hall A: Upcoming Program up to May 2012 Shutdown for 12-GeV installation Removed from schedule due to extended time needed for g2p /Gep transitions Hall A submitted draft plan for initial operations in FY14- FY16 to Director, expected to continue iterations in 2011 MIE for Super Bigbite System submitted to DOE, DOE science & technical review scheduled for October Draft MIE proposal for Moller experiment in hand

Year (Expt. #) ExperimentMajor Installation TasksSpecial Accel. Requirements Scientific Rating PAC Days FY2010 E E Eg6: DVCS and meson spectroscopy on 4 He Modified e1-DVCS setupStandard (E>5.9GeV) A, A-45 E E E E E G9 – Frost Missing N* Resonances (completion – started in 2008) Frozen spin targetStandard 3 A-, 2B+91 (remaining 60 days here) Install PRIMEx-II FY2011 E08-023PRIMEx-IIRe-Install PRIMExBeam StabilityA-20 E07-005EG5-Two Photon exchange in elastic e + p/e - p scattering Installation of conversion/target apparatus StandardA35 Install HDIce & Commission E06-101G14 – N* Searches (HDIce) (& electron test) HD polarized targetStandardA7 Accelerator Down for 12 GeV work FY2012 Accelerator Down for 12 GeV work E E E G14 Completion, then DVCS and SIDIS w/ HDIce Target Conversion of HD polarized target for electron beam operation StandardA, A and A-65 Technical feasibility to be established Almost … Hall B: Ongoing 6 GeV Program

HDice commissioning April-May/11 In-beam Cryostat (IBC) passed ASME pressure-code tests IBC installed in CLAS and aligned LHe circuit cooled; auto-fill from ESR established magnets (3 superconducting, 1 normal) commissioned at full current in-beam NMR successfully tested test transfer of solid HD from HDice Lab -to- Hall B –to- IBC low target temperatures prevented by blocked capillary First photo sent to us from HDIce in Hall B April 2011

HDice commissioning May-August/11 Blocked capillary was found to be piece of low-tech solder Achieved 48 mK July 31, 2011 (and I believe they reached 43 mK in the end) Produced additional three spare polarized target batches in July/August IBC moved to Hall B again last week Start cooling when ESR availability permits Need to do HD spin transfer tests in Hall

Beam-spin asymmetry for π 0 SIDIS A 5.75 GeV polarized electron beam was used with CLAS to measure the azimuthal dependence of the beam spin asymmetry for in a large x B, and P T range. Significant asymmetries are observed for 0.3<P T <0.7 GeV and in the range x B ≤ 0.4. Structure function F LU receives contributions from contributions from the convolution of twist-2 and twist-3 distribution and fragmentation functions, e.g. twist-2 Boers-Mulders DF, Collins FF and twist-3 DFs e and g T The observed asymmetry for π 0 suggests that the major contribution to pion beam SSA originates from spin-orbit correlations. ep  e’π 0 X M. Aghasyan et al. (CLAS), arXiv: , PLB accepted

Year (Expt. #) ExperimentMajor Installation TasksSpecial Accel. Requirements Scientific Rating PAC Days FY2010 E05-115HKS/HES (completion)Run to completionEnergy stability of 10 -4, Position stability < 100  m A-20 E08-016Q Weak (Install and begin commissioning) Major installation 6 months Complete overhaul of Hall C beamline New Polarimeter Major Cryo Load See Published Beam Specs. A198 FY2011 E08-016Q Weak (complete commissioning and run Phase I) See Published Beam Specs. A198 Accelerator Down for 12 GeV work FY2012 Accelerator Down for 12 GeV work E08-016Q Weak (run Phase II)See Published Beam Specs. A198 Now Underway Hall C: Ongoing 6 GeV Program

Hall C: Qweak status σ = 236 ppm Asymmetry Width Beam: routine data-taking at 165 ~88% polarization (and tests up to 180  A) Helicity-correlated properties acceptable! Status at 05/13/11 Precision measurement of the proton’s weak charge in the simplest system Search for parity-violating new physics up to the ~ 2 TeV scale No show-stoppers found, on track for proposed 4% precision on Q p Weak Above: 6.5 minutes of 165 μA Total detected rate = ~5.83 GHz Pure counting statistics: ~215 ppm + detector energy resolution -> 232 ppm + beam current normalization -> 235 ppm agrees with data

Evolution of PVES Helicity Correlated Beam Properties Qweak Run Average 8 ± 15 x: 3.9 ± 0.5 y: -5.7 ± 0.5 x’: ± 0.02 y’: ± 0.02

The QWEAK Experiment: Measurement of the Proton’s Weak Charge Elastic ep Scattering Parity-Violating Asymmetry Anticipated constraints if Q P W is consistent with the Standard Model. MS Theory Curve : J. Erler, M. J. Ramsey-Musolf et al., See Particle Data Group 2010 Anticipated Q P W uncertainty: Run I (completed) Run I + Run II Q (GeV) First direct measurement of the proton’s weak charge. Precision determination of the neutral current weak couplings to the quarks (C 1u & C 1d ). Mass scale reach for parity-violating new physics at expected final uncertainty (95% CL) is ~2.3 TeV. Isovector weak charge sin 2  W Q P W = - 2 (2C 1u + C 1d ) Young, Carlini, Thomas & Roche, PRL Isoscalar weak charge

The TAC Process Please note that for this PAC, we have asked a team of experienced and critical scientists, representing all Hall groups to look at some of the more technically challenging proposals. You will find the comments of this technical review attached to the individual reports. Our hope is, that this will be useful to both the PAC and the experiment proponents, and adds a layer of coherence to the technical review process. If a proposal was selected, this simply reflects our feeling that the proposal could benefit from this independent technical review. On the other hand, if a proposal was not selected, it does not mean it will not have technically challenging components. We welcome any feedback you might have on the use of this independent technical review process. Added for PAC38 an independent technical review process, and tried this on five proposals

The 12 GeV PAC Process (cont.) Planning the Initial Operation in Each Hall Following the model used for the initial CEBAF program, ~2-3 years before start of 12 GeV operation hall-by-hall: Each hall will provide for PAC review and comment (and potential improvement) a “commissioning and early running” plan folding in guidance of DOE/NP on early operations in FY14-FY16. The collaboration’s tradeoff between the best possible science and the realities of commissioning equipment. 3 years after the start of physics in each hall, jeopardy will begin. Status: Hall A early draft submitted to Director and iterations ongoing, Hall B plan started, Hall C plan just discussed at Summer workshop. Submit all for PAC review and comments Summer 2012?