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Q weak Overview and Target Status

Q weak Overview and Target Status. Silviu Covrig Hall C for the Q weak Collaboration Hall C Users Meeting January 23, 2010. g U(1).  W. g SU(2). Why Measure Q weak (p). Q w (p) is a fundamental property of the proton, never before measured

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Q weak Overview and Target Status

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  1. Qweak Overview and Target Status SilviuCovrig Hall C for the Qweak Collaboration Hall C Users Meeting January 23, 2010

  2. gU(1) W gSU(2) Why Measure Qweak(p) Qw(p) is a fundamental property of the proton, never before measured Being suppressed in the SM a 4% measurement may provide a window into parity violating physics at the TeV energy scale, complementing colliders It is a standalone precision determination of the Weinberg angle at low Q2 For a useful check of the running of sin2qw it’s relative uncertainty has to be <1% Hall C Users Meeting, January 23, 2010

  3. sin2θW in the Renormalization Scheme Hall C Users Meeting, January 23, 2010

  4. Parity Violation Asymmetry θ θ Q2,θ 0 e- e- h+ h- target target where For Qweak optimum Q2 ~ 0.03 (GeV/c)2 Hadronic form factor correction: from G0, SAMPLE, Happexx, PV-A4 Hall C Users Meeting, January 23, 2010

  5. Basic Qweak Parameters Parameter Value Beam Energy 1.165 GeV Polarization 85% Current 150-180 A LH2 Target 35 cm, 2500 W Production Running Time 2544 hours Acceptance: q, j, DW 8⁰ ± 3⁰, , 37 msr Acceptance Averaged Q2 < Q2 > = 0.026 (GeV/c)2 Acceptance Averaged Physics Asymmetry < A > = -0.234 ppm Acceptance Averaged Expt'l Asymmetry < A > = -0.200 ppm Integrated Cross Section 4.0 b Integrated Rate (all sectors) 6.5 GHz (.81 GHz / sector) Hall C Users Meeting, January 23, 2010

  6. The Qweak Experiment APV ≈ -200 ppb, DAPV ≈ 5 ppb Beam Properties • Gzero 500 ppb • HAPPEX 2 130 ppb • TRIUMF E497 35 ppb • SLAC E158 17 ppb • Qweak 5 ppb Hall C Users Meeting, January 23, 2010

  7. The Qweak Apparatus Hall C Users Meeting, January 23, 2010

  8. Qweak Magnet: QTOR • Toroidal magnet with 8 resistive coils • 4.3 m long / 1.5 m wide / ~3300 kg/coil • Tm 9500 Amps 1.2 MW water cooled Power Supply Hall C Users Meeting, January 23, 2010

  9. Qweak Detectors • Main Detectors • All 8 bars assembled in their light tight boxes • Remaining parts (exoskeleton & support frames) are built • 1st bars ready to install late Feb • Tracking System Region I = GEMs Region II = HDC Region III = VDC Both built 4+1 built 4 built Hall C Users Meeting, January 23, 2010

  10. New Hall-C Compton Polarimeter • Compton Polarimeter can run all the time • Photon and electron coincidences greatly reduce systematic uncertainties due to backgrounds. • < 1% precision is possible by cross-calibrating with existing Møller polarimeter. • Hall C Møller <1% precision, but needs dedicated low current runs Hall C Users Meeting, January 23, 2010

  11. Qweak Target Design First LH2 target at JLab designed with Computational Fluid Dynamics (CFD) – FLUENT Cryogenic Loop Highlights 54 liters, 2500 W LH2 centrifugal pump: 15 l/s (1 kg/s) flow @ <1.5 psid Hybrid heat exchanger: 27 l, both 4 K and 15 K He coolant High power heater: 2500 W Cell 35 cm long in beam, 7.8 liters conical cell LH2 flows transversely to the beam axis @ <v> ~ 2.9 m/s Steady-state uniform heating (Δρ/ρ)BV ~ 0.7%, transient rastered heating ~ 1.1% Hall C Users Meeting, January 23, 2010

  12. fh • APV measured in helicity pairs + - + - + - … • Counting statistics • Target density fluctuations • r = 5% 10% longer running • Target density reduction • 10% @Irun 10% longer running 2Th LH2 Target Systematics for Parity Violation Hall C Users Meeting, January 23, 2010

  13. The Qweak Target CAD model Cryogenic loop during assembly Centrifugal pump 30 Hz, 15 l/s, 1.5 psi Hybrid Heat Exchanger 2500 W Cell Block Hall C Users Meeting, January 23, 2010

  14. Flow Pattern e- beam 8⁰±3⁰ Acceptance Δpcell = 0.262 psid @ 1 kg/s mass rate Hall C Users Meeting, January 23, 2010

  15. Density Reduction Δρ/ρ (%) e- beam Boiling LH2 flow Heating 180 μA: LH2 245 W/cm3 Al 3950 W/cm3 7.5 liters 68 cm Hall C Users Meeting, January 23, 2010

  16. Qweak Target Safety Hydrogen concentration in normal air 4 < cV <74 % : deflagration 18< cV < 54 % : detonation Sub-sonic waves Shock Waves 4 kg of LH2 in 2 metal boundaries Safety incidents: • Relief (Sudden Loss of Vacuum): 105g/s Δp = 1 atm (ø pipe>2”) • Vent (cryo-loop breaks), with fluent: 210 g/s Δp < 1 atm (ø pipe>4”) • Release: hydrogen escapes into Hall C • ODH: none • Flammability: possible (556 MJ from burning 4 kg of hydrogen) 16 Hall C Users Meeting, January 23, 2010

  17. Case Study: Rastered Beam Heating Heating densities: same as Qweak cell Raster fx = 24960 Hz fy = 25080 Hz Transient simulation in fluent with ts = 2.25 μs Beam Direction 18 Hall C Users Meeting, January 23, 2010

  18. Schedule Highlights Installation period Nov 2009 – May 2010 Readiness Review July 20, 2009 Target Safety and Design Review Sep 4, 2009 (Passed) Commissioning May 25, 2010 – July 22, 2010 First Run Sep 06, 2010 – May 02, 2011 Second Run Nov 07, 2011 – May 14, 2012 Hall C Users Meeting, January 23, 2010

  19. The Qweak Collaboration (Funded by DOE, NSF, NSERC and the State of Va) D. Androic, D. Armstrong, A. Asaturyan, T. Averett, R. Beminiwattha, J. Benesch, J. Birchall, P. Bosted, C. Capuano,R. D. Carlini1 (Principal Investigator), G. Cates,S. Covrig, M Dalton, C. A. Davis, W. Deconinck, K. Dow, J. Dunne, D. Dutta, R. Ent, J. Erler, W. Falk, H. Fenker,J.M. Finn, T. A. Forest, W. Franklin, M. Furic, D. Gaskell, M. Gericke, J. Grames, K. Grimm, D. Higinbotham, M. Holtrop, J.R. Hoskins, K. Johnston, E. Ihloff, M. Jones, R. Jones, K. Joo, J. Kelsey, C. Keppel, M. Khol, P. King, E. Korkmaz, S. Kowalski1,J. Leacock, J.P. Leckey, J. H. Lee, L. Lee, A. Lung, S. MacEwan, D. Mack, R. Mahurin, J. Mammei, J. Martin, D. Meekins, A. Micherdzinska, A. Mkrtchyan, H. Mkrtchyan, N. Morgan, K. E. Myers, A. Narayan, Nuruzzaman, A. K. Opper, S. A. Page1, J. Pan, K. Paschke, S. Phillips, M. Pitt, B. (Matt) Poelker, Y. Prok, W. D. Ramsay, M. Ramsey-Musolf, J. Roche, B. Sawatzky, N. Simicevic, G. Smith2, T. Smith, P. Solvignon, P. Souder, D. Spayde, R. Suleiman, E. Tsentalovich, W.T.H. van Oers, B. Waidyawansa, W. Vulcan, D. Wang, P. Wang, S. Wells, S. A. Wood, S. Yang, R. Young, X. Zheng, C. Zorn 1Spokespersons 2Project Manager College of William and Mary, University of Connecticut, Instituto de Fisica, Universidad Nacional Autonoma de Mexico, University of Wisconsin, Hendrix College, Louisiana Tech University, University of Manitoba, Massachusetts Institute of Technology, Thomas Jefferson National Accelerator Facility, Virginia Polytechnic Institute & State University, TRIUMF, University of New Hampshire, Yerevan Physics Institute, Mississippi State University, University of Northern British Columbia, Ohio University, Hampton University, University of Winnipeg, University of Virginia, George Washington University, Syracuse University, Idaho State University, University of Connecticut, Christopher Newport University, University of Zagreb Hall C Users Meeting, January 23, 2010

  20. Low Energy Weak Neutral Current Standard Model Tests E158 : δ(sin2 qW ) ~ 0.54% MOLLER: δ(sin2 qW ) ~0.1% Qweak : δ(sin2 qW ) ~ 0.3% APV 133Cs : δ(sin2 qW ) ~ 0.83% Hall C Users Meeting, January 23, 2010

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