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Diboson physics @ CDF 

Diboson physics @ CDF . Alberto Annovi INFN - Frascati. The CDF detector @ Fermilab. Muon Extension |  |<1.1. Central Muon |  |<0.6. Solenoid. Fwd Muon 1<|  |<1.5. m. e. HAD Calorimeter. Drift Chamber. EM Calorimeter. Silicon Microstrip Tracker. n. e. Physic Motivation.

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Diboson physics @ CDF 

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  1. Diboson physics @ CDF  Alberto Annovi INFN - Frascati

  2. The CDF detector @ Fermilab Muon Extension ||<1.1 Central Muon ||<0.6 Solenoid Fwd Muon 1<||<1.5 m e HAD Calorimeter Drift Chamber EM Calorimeter Silicon Microstrip Tracker Alberto Annovi, INFN - Frascati n e

  3. Physic Motivation • Dibosons are a unique probe of the triple gauge couplings • Measure the couplings between g , W, and Z • Couplings can depend on the q2 • Tevatron has the highest q2 available • Anomalous couplings can affect cross-sections and kinematics pp  H WW, pp -> WH -> Wbb ..may be hiding in the diboson data Alberto Annovi, INFN - Frascati

  4. W + g production Event selection: W  lepton + n g with ET>7 GeV, DR(l, g)>0.7 Sensitive to WWg aTGC http://www-cdf.fnal.gov/physics/ewk/2007/wgzg/ Alberto Annovi, INFN - Frascati

  5. Z+g production & aTGC limits 1 fb-1 (ee), 2 fb-1 (mm) • Sensitive to ZZg aTGC • Event selection: • 2 leptons (ET>20 GeV) • mll > 40 GeV • central photon ET>7 GeV • DR (lep-g) > 0.7 ISR FSR http://www-cdf.fnal.gov/physics/ewk/2008/Zgamma/ σobs = 4.6 ± 0.2 (stat) pb ± 0.3 (syst) ± 0.3 (lum) σNLO = 4.5 ± 0.3 pb s(ISR): Mμμγ > 100 GeV/c2 σobs = 1.2 ± 0.1 (stat) ± 0.2 (syst) ± 0.1 (lum) pb Alberto Annovi, INFN - Frascati

  6. a WW  llnn event @ CDF Neutrinos show up as missing transverse energy WW will produce em events, while Drell-Yan is only ee and mm

  7. WW  llnn data selection Events prediction and backgrounds • Trigger lepton ET (pT) > 20 GeV • Second lepton ET (pT) > 10 GeV • Include also isolated tracks • Supress ttbar  WWbbbar <= 0 jets (ET>15 GeV, |h|<2.5) • Drell-Yan is O(105) bigger suppress w/ Missing ET transv. to each lepton (jet) > 25 GeV • (> 15 GeV) for em events • Mll> 16 GeV suppress HF Systematic errors only Alberto Annovi, INFN - Frascati

  8. WW Cross Section with 3.6 fb-1 Likelihood fit of Matrix Element Likelihood ratio MCFM used for Matrix elements input WW xsec @ 15% !! MC@NLO + CTEQ6.6 PRD78, 013008 Analysis web page: http://www-cdf.fnal.gov/physics/ewk/wwllll/index.html

  9. Extended leptons All multi-leptons (e, m) analyses use extened leptons to increase acceptance Alberto Annovi, INFN - Frascati

  10. WZ xsec & WWZ aTGC Select events with 3 leptons + Z l l + W  l + n Sensitivity to the WWZ vertex coupling. Unique access to WWZ separately from the WWγ coupling. Alberto Annovi, INFN - Frascati

  11. WZ production results http://www-cdf.fnal.gov/physics/ewk/2007/WZ_2fb/ s(WZ) = NLO cross section 3.7 ± 0.3 pb Alberto Annovi, INFN - Frascati

  12. WWZ aTGC limits from Z0 pT 1D limits 2D limits http://www-cdf.fnal.gov/physics/ewk/2008/WZatgc/ High-pT region sensitive to aTGC Alberto Annovi, INFN - Frascati

  13. Z0Z0 production Expected s*BR O(10fb) Two signatures: • Z0Z0 l+l-l+l- • Intensive use of extended leptons • s*BR ≈ 6.3 fb • Z0Z0 l+l- + • s*BR ≈ 38 fb Alberto Annovi, INFN - Frascati

  14. Z0Z0 production 2 leptons + MET combined 4lep 2lep+MET s(Z0Z0) = NLO prediction is s(Z0Z0) = 1.4 ± 0.1 pb http://www-cdf.fnal.gov/physics/ewk/2008/ZZ/ PRL 100, 201801 (2008) Alberto Annovi, INFN - Frascati

  15. aTGC in ZW/ZZ events Zll + W/Z  jets Data with MC expectations (Z+jets) • Trigger lepton ET (pT) > 20 GeV • Second lepton ET (pT) > 10 GeV • Include also isolated tracks • 76 < Mll < 106 GeV • suppress non Z production • 2 jets (cone DR<0.4, |h|<2.5) • select the 2 highest pT jets Med pT mJJ Use 3 pT(Zll) bins aTGC Med pT High-pT High-pT SM control 140 pT(Zll) mJJ

  16. aTGC in ZW and ZZ events BKG + LEP limit (medium pt bin) 95% CL limits on s(ZW+ZZ) by Z0 pT mJJ High pt bin fit (result -0.13±0.20) http://www-cdf.fnal.gov/physics/ewk/2008/ZZZatGC/ZZZaTGC.html … 2008/WWZaTGC/ Full table of aTGC limits in backup slide Alberto Annovi, INFN - Frascati

  17. WZ+WW -> lnjj (1.2fb-1) RESULTS: NN selection cut NSignal = 410 ± 212(stat) ± 107(sys) events σ × Br = 1.47 ± 0.77(stat) ± 0.38(sys) pb 95% CL σ × Br < 2.88 pb SM: σ × Br = 2.09 ± 0.14 pb http://www-cdf.fnal.gov/physics/ewk/2008/wwwz/ Update in progress: see APS meeting in Denver mJJ

  18. Search for VV  MET + jets WW, WZ, ZZ Four Pillars of This Analysis • Select jj+MET events • Benefited from L2 met/cal trigger upgrade • doi: 10.1109/NSSMIC.2006.354160 • Acceptance to νν and lνevents (WW, WZ, ZZ) • QCD rejection: MetModel • Reduced to only 16% out of selected events • Remaining QCD: based on Δφ(calMET-trkMET) • EWK mJJ shape: checked with γ+jj • Significantly reduces systematics n j n, lep j • SELECTION: • MET > 60 GeV • 2 jets ET>25, |h|<2.0 • MET significance > 4 • MET-jet df > 0.4 Alberto Annovi, INFN - Frascati

  19. First Had. Coll. Observation of VV  leptons + jets Dibosonphyics entered the jet era!!! 5.3s significance s(WW+WZ+ZZ) 18.0 ± 2.8(stat) ± 2.4(syst) ± 1.1(lumi) pb SM: 16.8±0.5 pb (MCFM + CTEQ6M) PRL just submitted! arXiv:0905.4714 Fermilab result of the week: http://www.fnal.gov/pub/today/

  20. Conclusions • Significant DiBoson samples being collected • Measuring Triple Gauge Couplings at high-q2 • First observation of diboson with leptons+jets • Opens the way to diboson studies with jets • The Higgs is getting closer CDF preliminary includes recent updates of published papers Alberto Annovi, INFN - Frascati

  21. BACKUP Alberto Annovi, INFN - Frascati

  22. aTGC limits from ZW and ZZ ZZ Alberto Annovi, INFN - Frascati

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