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PVDIS

PVDIS. Outline. Review of Physics and how to optimize spectrometer Summary of Progress Open Issues. PVDIS: Electron-Quark Scattering. A. V. V. A. Moller PV is insensitive to the C ij. PV elastic e-p scattering, APV.

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PVDIS

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  1. PVDIS PVDIS overview

  2. Outline • Review of Physics and how to optimize spectrometer • Summary of Progress • Open Issues PVDIS overview

  3. PVDIS: Electron-Quark Scattering A V V A Moller PV is insensitive to the Cij PV elastic e-p scattering, APV C1u and C1d will be determined to high precision by Qweak, APV Cs PV deep inelastic scattering C2u and C2d are small and poorly known: one combination can be accessed in PV DIS New physics such as compositeness, leptoquarks: Deviations to C2u and C2d might be fractionally large PVDIS overview

  4. Deep Inelastic Scattering e- e- * Z* X N a(x) and b(x) contain quark distribution functions fi(x) For an isoscalar target like 2H, structure functions largely cancel in the ratio at high x at high x At high x, APV becomes independent of x, W, with well-defined SM prediction for Q2 and y 0 New combination of: Vector quark couplings C1q Also axial quark couplings C2q 1 Sensitive to new physics at the TeV scale Unknown radiative corrections for coherent processes PVDIS: Only way to measure C2q PVDIS overview

  5. Strategy: • measure or constrain higher twist effects at x ~ 0.5-0.6 • precision measurement of APV at x → 0.8 to search for CSV Search for CSV in PV DIS • u-d mass difference • electromagnetic effects • Direct observation of parton-level CSV would be very exciting! • Important implications for high energy collider pdfs • Could explain significant portion of the NuTeV anomaly For APV in electron-2H DIS: Sensitivity will be further enhanced if u+d falls off more rapidly than u-d as x  1 PVDIS overview

  6. Higher Twist Subject of a workshop at Madison, Wisconsin • APV sensitive to diquarks: ratio of weak to electromagnetic charge depends on amount of coherence (elastic He vs PVDIS) • Do diquarks have twice the x of single quarks? • If Spin 0 diquarks dominate, likely only 1/Q4 effects PVDIS overview

  7. Need Full Phenomenology Start with Lorentz Invariance There are 5 relevant structure functions BIG Small; use νdata (Higher twist workshop at Madison, Wisconsin) PVDIS overview

  8. Why HT in PVDIS is Special Start with CVC (deuteron only) Bjorken, PRD 18, 3239 (78) Wolfenstein, NPB146, 477 (78) Zero in QPM Isospin decomposition before using PDF’s HT in F2 may be dominated by quark-gluon correlations Higher-Twist valance quark-quark correlations Vector-hadronic piece only PVDIS overview

  9. Quark-Quark vs Quark-Gluon What is a true quark-gluon operator? Parton Model or leading twist Quark-gluon diagram u u u d Quark-gluon operators correspond to transverse momentum QCD equations of motion Di-quarks Might be computed on the lattice PVDIS overview

  10. OOPS: Higher Twist in b(x) is now Background Talks by Mantry and Owens on this subject are scheduled for PAVI11 These hadronic corrections can be obtained from charged-current neutrino scattering data PVDIS overview

  11. Statistical Errors (%) vs Kinematics Strategy: sub-1% precision over broad kinematic range for sensitive Standard Model test and detailed study of hadronic structure contributions Error bar σA/A (%) shown at center of bins in Q2, x 4 months at 11 GeV 2 months at 6.6 GeV PVDIS overview

  12. Coherent Program of PVDIS Study Strategy: requires precise kinematics and broad range Fit data to: C(x)=βHT/(1-x)3 • Measure AD in NARROW bins of x, Q2 with 0.5% precision • Cover broad Q2 range for x in [0.3,0.6] to constrain HT • Search for CSV with x dependence of AD at high x • Use x>0.4, high Q2, and to measure a combination of the Ciq’s Errors on fit used to optimize spectrometer. PVDIS overview

  13. Sensitivity with PVDIS PVDIS overview

  14. Sensitivity: C1 and C2 Plots 6 GeV World’s data PVDIS Precision Data PVDIS Qweak Cs PVDIS overview

  15. PVDIS on the Proton: d/u at High x Independent FOM Deuteron analysis has large nuclear corrections (Yellow) APV for the proton has no such corrections (complementary to BONUS) 3-month run The challenge is to get statistical and systematic errors ~ 2% PVDIS overview

  16. Which Magnet? Criteria are: • Acceptance (for 30 sectors) • Resolution (Probably non-issue) • Length of Cerenkov detectors—big issue? PVDIS overview

  17. Possible Magnets • BaBar • CDF • CLEO • Zeus • Hall D For PVDIS, we haven’t ruled out any of these magnets. (Need 5 Monte Carlo’s) PVDIS overview

  18. GEM Tracking • GEM wires not orthogonal. • GEM produces analog output that must be interpreted. • Plan to use code developed for SBB spectrometer. Will determine number of planes required. PVDIS overview

  19. MC Ready for New Issues • Momentum calibration. Need MC • Accidentals and dead time. Trigger: 10 kHz/sector; 100x more pions. • Errors due to pion backgrounds (1% contamination?). PVDIS overview

  20. Higher-Twist fit to ν-Data PVDIS overview

  21. A New Design for Precision PV DIS Physics Over a Broad Kinematic Range • High Luminosity on LH2 & LD2 • Better than 1% errors for small bins • x-range 0.25-0.75 • W2 > 4 GeV2 • Q2 range a factor of 2 for each x • (Except x~0.75) • Moderate running times • Solenoid (from BaBar, CDF or CLEOII ) • contains low energy backgrounds (Moller, pions, etc) • trajectories measured after baffles • Fast tracking, particle ID, calorimetry, and pipeline electronics • Precision polarimetry (0.4%) PVDIS overview

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