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Tevatron Electroweak Results And Electroweak Summary

Tevatron Electroweak Results And Electroweak Summary. Sean Mattingly Brown University For the CDF and DZero Collaborations. XXIV Physics in Collision Boston, MA 29 June 2004. p. p. e, m. e + , m +. q. q. Z 0 / g *. W ±. BR = ~10%. BR = ~3%. n. e - , m -. p. q’. p. q.

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Tevatron Electroweak Results And Electroweak Summary

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  1. Tevatron Electroweak ResultsAnd Electroweak Summary Sean Mattingly Brown University For the CDF and DZero Collaborations XXIV Physics in Collision Boston, MA 29 June 2004

  2. p p e,m e+, m+ q q Z0/g* W± BR = ~10% BR = ~3% n e-, m- p q’ p q Electroweak Physics at the Tevatron • W and Z production • Well understood event signatures • Leptonic decay modes avoid high jets backgrounds • Increase understanding of detector by studying W/Z production • Cross sections are relatively well known and high • High statistics and clean event signatures  precision measurements such as… Sean Mattingly XXIV PiC 29 June 2004

  3. Tevatron Electroweak Measurements • W production • Decays to e,m,t lepton universality • Charge asymmetry  constrain PDFs • Transverse mass distribution  direct W mass & width • Constrain Higgs mass • Z production • Search for Z’ resonances • Forward-backward asymmetry  sin2(qw), quark couplings • Combined W/Z • Ratio of W/Z cross sections * BR  indirect W width • Diboson production - WW/WZ/Wg(g)/Zg(g) • Triple & quartic gauge couplings • W/Z/Diboson production are important backgrounds for top, Higgs and SUSY production Sean Mattingly XXIV PiC 29 June 2004

  4. W/Z Event Signatures Z production e+,m+ q (LEP) q Hadronic Recoil e-,m- W production n  Can’t measure pZ of n q’ q (LEP/TeV) Hadronic Recoil e,m Sean Mattingly XXIV PiC 29 June 2004

  5.  = -1  = -2 Detectors • DZero Run II upgrades • 2T solenoid, inner tracking • Preshower • m system/shielding • Trigger, DAQ • CDF Run II upgrades • Inner tracking • Forward calorimeter • Extended m system • Trigger, DAQ • Run II Luminosity Typically: ~6 x 1031 / cm2 s Record: 8.5 x 1031 / cm2 s Delivered: ~570 pb-1 Recorded: ~400 pb-1 / expt ~100K Zs, ~10M Ws /lept chan Goal: 4.4 fb-1 by end FY 09 DZero Analyses: 42-162 pb-1 CDF Analyses: 65-200 pb-1 Sean Mattingly XXIV PiC 29 June 2004

  6. Analysis Methods • Triggers • Electrons: EM calorimeter • Muons: track + muon system • Electron ID • High ET isolated EM calorimeter cluster usually w/ track match • Muon ID • High ET isolated track matched to muon detector track or calorimeter MIP • Z candidates • 2 leptons w/ invariant mass consistent with Z mass • W candidates • 1 lepton & missing ET > 25 GeV • ID efficiencies measured in Z events • Primary backgrounds determined using data jet events Sean Mattingly XXIV PiC 29 June 2004

  7. s*BR(Z  ee) • Two electrons, ET > 25 GeV • DZero: |h| < 1.1, CDF: full detector (1st EM central) • Small backgrounds from jets, Z  tt,(DY correction) DZero Run II Preliminary Bkg Bkg+MC Signal Data No track match L=42 pb-1 Sean Mattingly XXIV PiC 29 June 2004

  8. s*BR(Z  mm) • Two opposite charged muons, pT > 15-20 GeV • CDF: |h| < 1.0, DZero |h|< 1.8 • Very small backgrounds : jets(b), Ztt, cosmics, (DY corr.) Sean Mattingly XXIV PiC 29 June 2004

  9. s*BR(W  en) • One electron, pT > 25 GeV, missing ET > 25 GeV • DZero: |h| < 1.1, CDF: central & plug • Backgrounds: jets, Wtn, Zee Points: Background Subtracted Data Histogram: Wen MC L=42 pb-1 Sean Mattingly XXIV PiC 29 June 2004

  10. s*BR(W  mn) • One muon, pT > 20 GeV, missing ET > 20 GeV • DZero: |h| < 1.6 (from initial lumi), CDF: |h| < 1.0 • Backgrounds: Zmm, Wtn, jets(b) L=17 pb-1 Sean Mattingly XXIV PiC 29 June 2004

  11. CDF/DZero Comparison • Similar efficiencies and purities • CDF: Includes forward electrons • DZero: Includes farther forward muons Sean Mattingly XXIV PiC 29 June 2004

  12. Van Neerven, Matsuura Van Neerven, Matsuura W/Z Cross Sections Summary Sean Mattingly XXIV PiC 29 June 2004

  13. Tree level NNLO QCD calc (Van Neerven) SM EWK Calculation PDG(LEP) Indirect W Width • CDF combined electron & muon channels Sean Mattingly XXIV PiC 29 June 2004

  14. Toward Higher Precision • Luminosity error 10%  6.5% • CDF and DZero use same luminosity constants • Added luminosity • Improved statistical errors • Smaller lepton ID systematics • Refined background estimates • Improved detector simulation • Energy scale (EM and Hadronic), detector geometry and material description • PDFs • Using CTEQ6 and MRST sets w/ error sets • Combine CDF and DZero results • Tevatron Electroweak working group • Standardized error reporting • Account for error correlations • http://tevewwg.fnal.gov Use precision measurements in electroweak fits (see 2nd part of talk) Sean Mattingly XXIV PiC 29 June 2004

  15. Physics with t • Zt(leptonic)t(1 pronghadronic) • Demonstrates visibility of tt resonances at the Tevatron • DZero: muonic decays + observe N p0, CDF: electronic decays D0 Run II preliminary L=68 pb-1 mt Visible Mass (GeV) Sean Mattingly XXIV PiC 29 June 2004

  16. Physics with t (cont) • Wtn (CDF) • Trigger on track + missing ET • Count tracks in 10o cone, veto on tracks in 30o cone • Reconstruct p0 with detectors at shower max • Combined mass < Mt • Backgrounds: Wmn, Wen, Ztt, jets Sean Mattingly XXIV PiC 29 June 2004

  17. e− p p q e+ Forward-backward Asymmetry • Z/g*  e+e- (CDF) • At Tevatron can measure at Z pole and above and below • Directly probes V-A, extract sin2qW and u/d couplings to Z Sean Mattingly XXIV PiC 29 June 2004

  18. W Charge Asymmetry • Wen (CDF) • Up-type quarks carry more average momentum • W+ boosted in p direction, W- boosted in p direction • Charge asymmetry as function of rapidity constrains PDFs • Cannot unambiguously determine W±’s direction (lost n) but e± direction carries W± direction information • Measure charge asymmetry using e± rapidity • Higher ETe± more closely aligned with W ± direction • Main constraints for forward rapidities • Ratio of u/d PDFs Sean Mattingly XXIV PiC 29 June 2004

  19. W Charge Asymmetry (cont) • Select W events and identify charge • 50 < MT < 100 GeV, no other EM object with ET > 25 GeV • Use calorimeter seeded tracking with forward silicon to determine charge out to |hdet| < 2 • Charge mis-ID rate measured using Zee • < 1% for |hdet| < 1.5, < 4% farther forward • Backgrounds bias asymmetry toward zero • Zee, Wtn subtracted using MC, jets using data Sean Mattingly XXIV PiC 29 June 2004

  20. Drell-Yan Invariant Mass Spectrum • CDF/DZero Compare to Drell-Yan • Set limits on Z’, extra dimensions, etc. • Improve on Run I limits, test new models 95% CL, M(Z’/SM) > 780 GeV 95% CL, M(Z’/SM) > 735 GeV Di-EM Mass (GeV) Sean Mattingly XXIV PiC 29 June 2004

  21. Diboson Production • Tevatron collisions can produce Wg(g), Zg(g), WW, WZ, ZZ • Probe the gauge structure of electroweak • Search for anomalous couplings • Improve diboson modeling • Diboson production backgrounds in searches for new physics • Leptonic decay modes • Minimize jet backgrounds Sean Mattingly XXIV PiC 29 June 2004

  22. Initial State Radiation WWg: Triple Gauge Coupling Final State Radiation Diboson Production: Wg • Wg(e/m)ng: Firstselect Wln events (CDF/DZero) • Add photon requirement: isolated EM, no track, shower max • Photon ET > 7-8 GeV, lepton-photon DR > 0.7, |hg| < 1.1 • Backgrounds: W+jet, Z+g, Z+jet, “leX”, Wtng D0 RunII preliminary W(e/m)ng L(e) = 162 pb-1 L(m) = 82 pb-1 Sean Mattingly XXIV PiC 29 June 2004

  23. Diboson Production: Wg Cross Sections Sean Mattingly XXIV PiC 29 June 2004

  24. Final State Radiation ZZg: Triple Gauge Coupling Initial State Radiation Diboson Production: Zg • Z(e/m)g (CDF) • Z selection + photon • Photon ET > 7 GeV, DR(lg) > 0.7, |hg| < 1.1 • Relative backgrounds smaller than for Wg • Main background: Z+jet Sean Mattingly XXIV PiC 29 June 2004

  25. Diboson Production: Zg Cross Section Sean Mattingly XXIV PiC 29 June 2004

  26. Diboson Production: WW • Two analyses from CDF • High purity: identify 2 leptons • High efficiency: identify 1 lepton + 1 isolated track • Backgrounds: DY, WZ/ZZ/Wg, Ztt, ttllX, fakes • HWW (CDF/DZero): See E. Nagy’s talk • Purity analysis • 2 high pT leptons • Opposite sign • Missing ET > 25 GeV • Veto if any high ET jets • Reject if dilepton mass near Z mass and (missing ET)/ (scalar summed ET) < 3 Sean Mattingly XXIV PiC 29 June 2004

  27. Diboson Production: WW (cont.) • Efficiency analysis • 1 high pT lepton + 1 isolated high pT track • Missing ET > 25 GeV • Veto if > 1 high ET jet • Reject (missing ET)/(scalar summed ET) < 5.5 NLO Ellis & Campbell: 12.5 ± 0.8 pb Sean Mattingly XXIV PiC 29 June 2004

  28. ZZ/WZ Final States • Look for leptonic final states (CDF) • 2-4 high pT leptons in e and m channels (194 pb-1) • ZZllll or llnn and WZlnll • Require one lepton pair to be consistent with Z mass • 5.1 ± 0.7 expected • 4 observed • 95% CL: s(ZZ/WZ) < 13.8 pb-1 • SM (Ellis & Campbell) = 5.2 pb Sean Mattingly XXIV PiC 29 June 2004

  29. Precision Electroweak Measurements And Electroweak Radiative Corrections • Large number of measurements from LEP, SLC and Tevatron • W mass/width (Tevatron, LEP-2) • Top quark mass (Tevatron) • Z-pole measurements (LEP, SLD) • Z lineshape parameters • Polarized leptonic asymmetries • Heavy flavor asymmetries and branching fractions • Hadronic charge asymmetry • In the SM, each observable can be calculated/fit in terms of • Dahad, as(MZ), MZ, MW, sin2qW, Mtop, Mhiggs, etc… • Higgs & top enter as ~1% radiative corrections • LEP Electroweak Working Group • ZFITTER, TOPAZ0 } Recent and future updates Sean Mattingly XXIV PiC 29 June 2004

  30. W Mass/Width • Tevatron W mass and width • From fits to MT spectrum • LEP-2 W mass and width • From reconstructing Ws • e+e-WWqqqq or qqln • Difference between two final states: DmW = 22 ± 43 MeV Sean Mattingly XXIV PiC 29 June 2004

  31. W Mass Prospects • Final CDF/DZero Run I W mass 80.452 ± 0.059 GeV } Errors decrease with larger Run II luminosity and Run II detector upgrades } Run II measurements of W charge asymmetry and Z rapidity distribution constrain PDF  reduce PDF uncertainty • Run II uncertainty goal 40 MeV per experiment • ~25 MeV combined (TEVEWWG) Sean Mattingly XXIV PiC 29 June 2004

  32. Top Quark Mass • DZero update on Run 1 result • Mtop = 180.1 ± 5.3 GeV • ~15% smaller error than previous • Preliminary CDF Run 2 results • See talk by A. Hocker • Not yet included in fits • Expected Run 2 accuracy: 2.5 GeV Sean Mattingly XXIV PiC 29 June 2004

  33. W and Top Mass in Electroweak Fit • Z-pole measurements • Use fit to indirectly predict W/top mass (LEP-1, SLD) • Direct and indirect agree • Test of SM • Both favor lighter Higgs LEPEWWG (indirect) (direct) Sean Mattingly XXIV PiC 29 June 2004

  34. Electroweak Fit: Top Mass • Predicted and measured Mtop in good agreement • Measurement uncertainty half of prediction uncertainty LEPEWWG Sean Mattingly XXIV PiC 29 June 2004

  35. Electroweak Fit: W Mass LEPEWWG • Predicted and measured MW in agreement • Measured MW not yet as accurate as prediction • Combined CDF/DZero Run II W mass: expect ~similar accuracy to prediction Sean Mattingly XXIV PiC 29 June 2004

  36. Electroweak Fit: Higgs Mass LEPEWWG A. Quadt • Fit using high Q2 (LEP, SLC, Tevatron) data • Most likely MHiggs = 113 ±6242 GeV • MHiggs < 237 GeV (95% CL) Year Sean Mattingly XXIV PiC 29 June 2004

  37. Electroweak Fit: Summary LEPEWWG • Fit to all observables • c2/Ndof = 16.3/13 • Largest pull from b AFB • 2.5s effect in opposite direction of next largest pull: Al(SLD) • Accurately predicts low Q2 measurements • Atomic parity violation • Moller scattering • NuTeV? Sean Mattingly XXIV PiC 29 June 2004

  38. n m/n W±/Z q q NuTeV’s Result • Paschos-Wolfenstein relation: neutrinos on isoscalar target sin2qW = 0.22773 ± 0.00135(stat) ± 0.00093(syst) [SM = 0.2226 ± 0.0004] Or…assumingsin2qW is in agreement (i.e. MW/MZ) • rn = 0.988 ± 0.004 3s effect • New physics? New particles, oscillations, etc… • Old physics? PDFs, non-isoscalar target, sea asymmetry, etc… Sean Mattingly XXIV PiC 29 June 2004

  39. Conclusion • Many Tevatron Run II electroweak measurements • Detector understanding increasing • ~200pb-1 of luminosity analyzed per experiment • Preliminary W mass measurements soon • TEVEWWG will combine CDF and DZero measurements • Standard Model describes large number of measurements with precision • Discrepancies can be interpreted as statistical fluctuations • Higgs mass constrained < 237 GeV, most likely MHiggs = 113 ±6242 GeV • Upcoming Tevatron Run 2 top quark and W mass measurements important components in Higgs mass constraints Sean Mattingly XXIV PiC 29 June 2004

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