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Exploring the Standard Model with JLab at 12 GeV

Exploring the Standard Model with JLab at 12 GeV. Standard Model tests: Beyond sin 2 ( q W ). e2ePV : Moller Scattering at 11 GeV DIS-Parity : Parity NonConserving Electron Deep Inelastic Scattering. For Dave Mack, Paul Souder, Michael Ramsey-Musolf, et al.

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Exploring the Standard Model with JLab at 12 GeV

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  1. Exploring the Standard Model with JLab at 12 GeV Standard Model tests: Beyond sin2(qW). e2ePV: Moller Scattering at 11 GeV DIS-Parity: Parity NonConserving Electron Deep Inelastic Scattering For Dave Mack, Paul Souder, Michael Ramsey-Musolf, et al.

  2. sin2(qW) measurements below Z-pole • NuTeV nA scattering: • 3s from Standard Model!!! • Fe target: PDF’s in iron? Nuclear corrections? • Atomic Parity Violation (APV): • Hard to understand theoretically. • Consistent with S.M. (plot is out of date) • Qweak (Jlab) • QweakPROTON • ¼ 2005-07 • E158-Moller • QWeakELECTRON • Final run 2003 Future measurements • Standard Model predicts sin2(qW) varies (runs) with Q2 • Non-S.M. physics may move measurements away from running curve. • Different measurements sensitive to different non-S.M. physics. • Well measured at Z-pole, but not at other Q2. Paul E. Reimer, Argonne National Laboratory

  3. Beyond sin2(qW): e.g. SUSY and Dark Matter NASA Hubble NGC3310 JLab QWeak (proton) and SLAC E158 Moller (QWe) anticipated limits. • What is Dark Matter? • S.M.: QWelectron and QWproton both measure 1-4sin2(qW). • SUSY: Loop contributions can change this by measurable amounts! hep-ph/0205183 RPV No SUSY dark matter Paul E. Reimer, Argonne National Laboratory

  4. e2ePV: Parity Violating Moller Scattering at 12 GeV D. Mack, W. van Oers, R. Carlini, N. Simicevic, G. Smith Paul E. Reimer, Argonne National Laboratory

  5. e2ePV: Moller Scattering at 12 GeV • Measurement of QWeak of the electron. • Very small asymmetry: • A|11 GeV¼ 9¢10-7 (1 – 4 sin2qW) ¼ 4¢10-8. • Near-vanishing of the tree-level asymmetry makes this measurement sensitive to • New physics at tree-level (e.g. Z0), • New physics via loops (e.g. SUSY loop contributions). • Restriction the available parameter space by a small amount is useful! • Is there room for JLab to improve on the SLAC E158 measurement? What type of apparatus would be needed? Paul E. Reimer, Argonne National Laboratory

  6. Moller sin2qW Error De-Magnification sin2(qW) ¼ 0.238 1 - 4 sin2(qW) ¼ 0.05 • Radiative corrections • Not all of which are suppressed (De-Magnified) by (1-4sin2(qW) • Reduce tree-level Moller asymmetry by ¼ 40% Paul E. Reimer, Argonne National Laboratory

  7. Moller 12 GeV vs. 48 GeV • Repeat SLAC-E158 Moller • Figure of merit: • A2 ds/dW/ Ebeam. • Factor of 4 better at SLAC. • All else equal, the advantage goes to the higher beam energy—but “all else” is not equal!! • JLab can have a clear advantage in luminosity. Paul E. Reimer, Argonne National Laboratory

  8. JLab 12 GeV Moller vs. SLAC E158 JLab’s advantage comes from the higher integrated luminosity available. Paul E. Reimer, Argonne National Laboratory

  9. Moller sin2(qW) Anticipated Uncertainties Clearly a competitive measurement of sin2qW is possible at 11 GeV which is competitive with the best single measurements below and at the Z-pole. Paul E. Reimer, Argonne National Laboratory

  10. Moller Detection Laboratory scattering angles are small!! • Detector Requirements: • Focus Moller electrons of momentum 4.5 GeV/c § 33%. • Toroidal magnet with 1/R field is well suited. • Field requirement are less and scattering angle larger than at SLAC • Detector Concept: • Drift scattered electrons to a collimator. • Focus electrons in a resistive toroidal magnet. • Drift electrons to detector ring. Paul E. Reimer, Argonne National Laboratory

  11. e2ePV Moller Conclusions hep-ph/0205183 RPV No SUSY dark matter • There is a small window for a Moller exp. at JLab to improve over SLAC E-158. • This improvement can have a significant impact on the range of allowable SUSY extensions. JLab QWeak (proton) and JLab e2ePV Moller (QWe) anticipated limits. Paul E. Reimer, Argonne National Laboratory

  12. DIS-Parity: Polarized e-deuterium Deep Inelastic Scattering Parity NonConservation Paul Reimer, Peter Bosted, Dave Mack Paul E. Reimer, Argonne National Laboratory

  13. Textbook Physics: Polarized e- d scattering • Repeat SLAC experiment (30 years later) with better statistics and systematics at 12 GeV Jefferson Lab: • Beam current 100 mA vs. 4 mA at SLAC in ’78 £ 25 stat • 60 cm target vs. 30 cm target £ 2 stat • Pe (=electron polarization) = 80% vs. 37% £ 4 stat • d Pe¼ 1% vs. 6% £ 6 sys Paul E. Reimer, Argonne National Laboratory

  14. DIS-Parity: Polarized e- deuterium DIS Longitudinally polarized electrons on unpolarized isoscaler (deuterium) target. C1q) NC vector coupling to q £ NC axial coupling to e C2q) NC axial coupling to q £ NC vector coupling to e Note that each of the Cia are sensitive to different possible S.M. extensions. Paul E. Reimer, Argonne National Laboratory

  15. DIS-Parity: Detector and Expected Rates • Expt. Assumptions: • 60 cm ld2/lH2 target • 11 GeV beam @ 90mA • 75% polar. • 12.5± central angle • 12 msr dW • 6.8 GeV§10% mom. bite • Rate expectations: • ¼ 1MHz DIS • p/e ¼ 1 ) 1 MHz pions • 2 MHz Total rate • dA/A = 0.5% ) 2 weeks (ideal) plus time for H2 and systematics studies. Will work in either Hall C (HMS +SHMS) or Hall A (MAD) hxi = 0.45 hQ2i = 3.5 GeV2 hYi = 0.46 hW2i = 5.23 GeV2 Q2 near NuTeV result—provide cross check on neutrino result. Paul E. Reimer, Argonne National Laboratory

  16. Uncertainties in Ad • Beam Polarization: • This drives the uncertainty! • QWeak also needs 1.4% • Hall C Moller claims 0.5%. • Higher twists may enter at low Q2: • This could be a problem. • Check by taking additional data at lower and higher Q2. • Possible 6 GeV experiment? • Ad to § 0.5% stat § 1.1% syst. (1.24% combined) What about Ciq’s? Paul E. Reimer, Argonne National Laboratory

  17. Extracted Signal—It’s all in the binning PDG: C1u= –0.209§0.041 highly C1d= 0.358§0.037 correlated 2C2u– C2d = –0.08§0.24 This measurement: d(2C1u– C1d) = 0.005 (stat.) d(2C2u– C2d) = 0.014 (stat.) Note—Polarization uncertainty enters as in slope and intercept Aobs = PAd/ P(2C1u–C1d) + P(2C2u–C2d)Y] but is correlated Paul E. Reimer, Argonne National Laboratory

  18. DIS-Parity determines 2C2u-C2d Combined result significantly constrains 2C2u–C2d. PDG 2C2u–C2d = –0.08 § 0.24Combined d(2C2u–C2d) = § 0.014 £ 17 improvement (S.M 2C2u – C2d = 0.0986) Paul E. Reimer, Argonne National Laboratory

  19. DIS-Parity: Conclusions • DIS-Parity Violation measurements can easily accomplished at JLab with the 12 GeV upgrade (beam and detectors) in either Hall A or Hall C. • Large asymmetry/quick experiment. • Requires very little beyond the standard equipment which will already be present in the halls. • Near NuTeV Q2. • Higher twist may be important d(2C1u – C1d) = 0.005 d(2C2u – C2d) = 0.014 Paul E. Reimer, Argonne National Laboratory

  20. JLab tests of the Standard Model • Measurements of sin2(qW) below MZ provide strict tests of the SM. • Measurements in different systems provide complementary information. • Moller Parity Violation can be measured at JLab at a level which will impact the Standard Model. • DIS-Parity violation measurement is easily carried out at JLab. hep-ph/0205183 RPV Weak Mixing Angle MS-bar scheme Jens Erler No SUSY dark matter Paul E. Reimer, Argonne National Laboratory

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