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Tevatron W/Z/  Results Part II Attack of the DiBosons

Tevatron W/Z/  Results Part II Attack of the DiBosons. 15th Topical Conference on Hadron Collider Physics Michael Kirby for the CDF and D0 Collaborations. Why study DiBoson production?. Heavy Boson + photon, Two Heavy Bosons

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Tevatron W/Z/  Results Part II Attack of the DiBosons

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  1. Tevatron W/Z/ Results Part IIAttack of the DiBosons 15th Topical Conference on Hadron Collider Physics Michael Kirby for the CDF and D0 Collaborations Michael Kirby, Duke University

  2. Why study DiBoson production? • Heavy Boson + photon, Two Heavy Bosons • Natural extension of well understood and measured W and Z production • Precise predictions available from many NLO calculations • Small cross sections provide challenge • Sensitive to non-Standard Model physics, internal structure of W and Z • Places limits on Anomalous Trilinear Couplings • Good confirmation of SU(2)LxU(1)Y structure of Electroweak sector Michael Kirby, Duke University

  3. DiBoson Production at the Tevatron Michael Kirby, Duke University

  4. The Tevatron at Fermilab • Tevatron proton anti-proton collider at Fermilab • EBeam = 980 GeV • 36x36 bunches with 396ns spacing • Increased instantaneous Luminosity • Typical:4 - 5 x 1031 cm–2 s-1 • Record: ~7.83 x 1031 cm–2 s-1 • Tevatron has delivered in total~500 pb-1 • Long term, by the end of FY09 • Base goal: 4.4 fb-1 Design: 8.5 fb-1 Michael Kirby, Duke University

  5. Oct Jan Apr Jul Oct Jan Apr Jul Oct Jan 2002 2003 2004 200 pb-1 64 pb-1 CDF Run I Delivered To Tape Store Number Detector Integrated Luminosity Michael Kirby, Duke University

  6. The D0 Run II Detector Michael Kirby, Duke University

  7. The CDF Run II Detector ||= 1. ||=2. Michael Kirby, Duke University

  8. W Production • Includes the Triple Gauge Coupling • Anomalous terms (, ) • SM (=0, =0) • Interference between ISR and TGC produces Radiation Amplitude Zero • only in SU(2)xU(1) group • After Detector Simulation LO MC NEVENTS Q(-l) Michael Kirby, Duke University

  9. SM SM ET(g) GeV DR(l,g) Anomalous Couplings In the ET=0 limit, couplings equated with classical magnetic dipole and electric quadrupole Michael Kirby, Duke University

  10. W Event Selection •  Selection • Central Track assoc.  hits • PT > 20 GeV • CDF - || < 1.0 • D0 - || < 2.0 • Electron Selection • EM Cluster > 25 GeV • Matched Track • Shower Shape Discrimination • CDF - |e| < 1.1, 1.2<|e| < 2.6 • D0 - |e| < 1.1, 1.6<|e| < 2.5 • Missing Tranverse Energy • > 20 GeV for  candidates • > 25 GeV for e candidates pT Photon Muon ET ET Neutrino ET Photon Electron ET ET Neutrino Michael Kirby, Duke University

  11. W Event Selection Cont CDF Et ()>7 GeV DØ Et ()>8 GeV R(,l)>0.7 |  |<1.1 Cal & trk-iso •  Selection • Central Calorimeter • Shower profile discrimination • Calor. and Track Isolation • ET > 7 GeV (CDF) • ET > 8 GeV (D0) • -lepton separation • R(l,)>0.7  0  Shower Maximum Detector Pre-shower Detector • Background dominantly from W + jets • leading 0 fakes photon in jets • Additional Bckgs - Z, W , misreconstruction Michael Kirby, Duke University

  12. W Results Measured (W)BR(Wl)= 19.9 2.7 (stat+sys) 1.1 (lumi) pb Measured (W)BR(Wl)= 19.3 6.7 (stat +sys) 1.2 (lumi) pb NLO Theory = 19.3 1.3pb NLO Theory = 16.4 0.4pb Michael Kirby, Duke University

  13. ET Results CDF Run 2 Preliminary 202/pb D0 Run 2 Preliminary 162/pb Michael Kirby, Duke University

  14. R(l,) Results D0 Run 2 Preliminary 162/pb Michael Kirby, Duke University

  15. W: l-ET Transverse Mass D0 Run 2 Preliminary 162/pb Michael Kirby, Duke University

  16. CDF Run 2 Preliminary 202/pb Cluster Transverse Mass Greater sensitivity to Anomalous Couplings and RAZ in high CTM region Michael Kirby, Duke University

  17. Z Production • No ZZ Triple Gauge Coupling in Standard Model at tree level • no Radiation Amplitude Zero • Anomalous terms(hi0, hZi0) • SM (hi0=0, hZi0=0) • Excellent cross check for W production • Anomalous terms can be related to the dipole and quadrupole moments Z Z Z Z l Michael Kirby, Duke University

  18. Z Event Selection •  Selection • Central Track • PT > 20 GeV • opposite charge • CDF - || < 1.0 • Electron Selection • EM Cluster > 25 GeV • CDF - |e| < 2.6 • Invariant Mass > 40 GeV • Photon selection • ET > 7 GeV • R(l,)>0.7 pT Photon Muon ET pT Muon ET Photon Electron ET Electron • Background from Z + jets ET Michael Kirby, Duke University

  19. Z Results Backgrounds Measured (Z)BR(Zll) = 4.5 0.5 (stat + sys) 0.3 (lumi) pb Note: (W)/(Z) ≈3 while (W)/(Z) ≈10 NLO Theory = 4.5 0.3pb (ET > 7 GeV, R(l,)>0.7) Michael Kirby, Duke University

  20. Z Results CDF Run 2 Preliminary 202/pb CDF Run 2 Preliminary 202/pb CDF Run 2 Preliminary 202/pb CDF Run 2 Preliminary 202/pb Michael Kirby, Duke University

  21. Z Results CDF Run 2 Preliminary 202/pb CDF Run 2 Preliminary 202/pb Michael Kirby, Duke University

  22. WW, WZ, and ZZ Production • Complementary probe of Triple Gauge Coupling • higher Boson and Lepton PT indicates Anom. Coup. • Small cross sections make for challenging measurement • Study using leptonic decays of the W and Z • Important foundation for Higgs searches Michael Kirby, Duke University

  23. CDF: WW (Two approaches) Two complementary approaches • Dileptons: l+,l-: identified e, • Reject 76<Mll<106 & ETsig <3.0 • ET>25 • No High Et jets • Opposite sign & Isolation • DY, Z •  WZ/ZZ, Z •  top dilepton •  Fakes • (Identified e,)+Iso track • Reject ETsig <5.5 in all Mll • ET>25 • Njets<=1 • Opposite sign & Isolation Missing ET Signifigance (GeV) High S/B Increased acceptance Michael Kirby, Duke University

  24. CDF: WW cross section NLO (Campbell & Ellis, 1999) WW=12.50.8 pb e, l+track Michael Kirby, Duke University

  25. CDF: WW Beyond SM ggHWW 140<MH<180GeV/c2 Anomalous TGC WWZ/WW Jet: >15 GeV Cone 0.4 Michael Kirby, Duke University

  26. WWee or ZZee ? Michael Kirby, Duke University

  27. ZW, ZZ study in Run II Select Zll • Event selections • Four lepton events • Signal: ZZ • Background: Z/W+jets, multijet • Three lepton events • Signal: ZZ, ZW • Background: Z/W+jets, multijet • Two lepton events • Signal: ZZ, ZW • Background: WW, Drell Yan, Top, W+jets Michael Kirby, Duke University

  28. ZW, ZZ study in Run II • Cross section upper limit consistent with SM prediction of 5.2 ± 0.4 pb 95% Conf Limit Michael Kirby, Duke University

  29. The Next Steps • Tevatron has excellent DiBoson production studies ongoing. • Will measure limits on Anomalous Triple Gauge Couplings • W, Z, WW, ZW, and ZZ • Establish baseline for other DiBoson production • Already have WW searches for Higgs production and improving upon understanding of HW production (see Michael Gold’s talk on Thursday) • Non-dilepton analyses are underway Michael Kirby, Duke University

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