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Recent Results from Tevatron

Recent Results from Tevatron. Complementarity. Higgs. Hints & Excesses. Legacy. Outline. Introduction Tevatron Recent Results Prospects & Conclusions. [ Thanks to all my Tevatron colleagues ]. Tevatron Performance. Over 10.5fb -1 delivered per experiment

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Recent Results from Tevatron

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  1. Recent Results from Tevatron

  2. Complementarity Higgs Hints & Excesses Legacy Outline • Introduction • Tevatron • Recent Results • Prospects & Conclusions [ Thanks to all my Tevatron colleagues ] Gavin Davies – IoP2011

  3. Tevatron Performance • Over 10.5fb-1 delivered per experiment • Expect up to ~12 fb-1 by Oct 2011 Average data-taking efficiency ~90% Results presented here use up to ~8fb-1 Many thanks to Accelerator Division 04/02 06/06 10/10 Gavin Davies – IoP2011

  4. A Wealth of Recent Results By way of example: http://www-d0.fnal.gov/Run2Physics/ResultsWinter2011.html Gavin Davies – IoP2011

  5. A Wealth of Recent Results And…. Gavin Davies – IoP2011

  6. A Wealth of Recent Results And ‘finally’… And likewise: http://www-cdf.fnal.gov/physics/physics.html Gavin Davies – IoP2011

  7. ‘Organising’ the Results.. Complementarity AFB(top) CP in heavy flavour decays top spin correlations high xgluon W asymmetry SUSY searches Higgs Legacy Hints & Excesses top mass top properties W mass CP in Bs See talk on thursday t’ top resonances Gavin Davies – IoP2011

  8. Top mass - Current Tevatron precision of 0.7% CDF alone now at 0.6% W mass Current Tevatron precision of 31MeV Legacy mH<117GeV Gavin Davies – IoP2011

  9. Other ‘Top’ Results • eg Production Asymmetry AFB Raw AFB Data: 0.0570.028 MC@NLO: 0.0170.004 lepton+jet dilepton Gavin Davies – IoP2011

  10. Other ‘Top’ & Electroweak Results • eg FCNC • eg sinqW World’s best limit World’s best for light quarks! Gavin Davies – IoP2011

  11. Complementarity • Proton-Antiproton: enables high precision CP measurements due to symmetric initial state eg D0→ K+K-& p+p- World’s best results ACP(D0 → π+π )= +0.220.24 0.11 % Gavin Davies – IoP2011

  12. ℓ+ Z/γ* ℓ- ℓ+ Z/γ* ℓ- Alternatively… σ(ditop+γ) =0.18±0.07 pb σ(ZZ) =1.35±0.45(stat )±0.15(syst)pb Gavin Davies – IoP2011

  13. Standard Model Higgs • Higgs mechanism • Additional scalar field in SM Lagrangian  mass to W,Z & fermions • Predicts neutral, spin 0 boson • But not its mass • Direct searches at LEP2 • mH> 114.4 GeV • Precision data favour a light Higgs • mH < 185 GeV if LEP2 limit included  Accessible at Tevatron (Not finding the Higgs boson will contradict SM & revolutionize particle physics…) Gavin Davies – IoP2011

  14. Higgs at the Tevatron Gavin Davies – IoP2011

  15. Strategy: Leave no stone unturned • All signal production and decay processes • eg W/Z+H and qqH at high mass • eg photons & taus, hadronic decays of W’s • Optimise leading channels • eg b-tagging & mass resolution at low mass • Constrain systematics with data • Improved final discriminants • eg neural networks, boosted decision trees… • Combine across all channels & experiments 95% CL limit / SM Gavin Davies – IoP2011

  16. Low Mass: A ‘usual’ suspect • One of most powerful, but challenging channels • Improved use of b-tagging information • 15% gain in sensitivity • Boosted decision trees • To reject multijet background • As final discriminant • Split into 1 and 2 b-tag samples Missing transverse energy Two high pT jets, acoplanar, b-tagged mH=115 GeV, 95% CL Expected: 4.0×SM Observed: 3.4×SM Gavin Davies – IoP2011

  17. ‘Low’ Mass: Additional channels • H → ττ • 2ndlargest BR at low mass • Tau pair + 1or 2 jets • Hgg • More data • Boosted decision tree • ~30% gain in sensitivity mH=115 GeV Expected: 15×SM Observed: 15×SM mH=115 GeV: Expected: 11×SM Observed: 20×SM Gavin Davies – IoP2011

  18. High Mass • New high mass combination for winter 2011 • All channels updated / improved • New channels CDF D0 Gavin Davies – IoP2011

  19. H+X → l+l- +missing ET • mH>135 GeV, H→W*W dominates • Clean - use gg → H production • W/Z+H, qqH also contribute • Subdivide • By jet multiplicity lepton quality • Use MVA • With differing inputs Gavin Davies – IoP2011

  20. Additional Channels W/Z H same sign dilepton Trileptons: WH Expected @ 160 6.4xSM Expected @ 160 4.3xSM gg→H→WW→lmqq gg→H→WW→tmnn Expected @ 160 7.8xSM Expected @ 160 5.1xSM Gavin Davies – IoP2011

  21. Combination • Two statistical approaches • Agree better than 5% over all masses • Operate on binned final discriminants • Systematics (& correlations) included • Rate and shape effects considered • Impact mitigated with constraints from data • gg→H: NNLO +NNLL • arXiv:0811.3458, arXiv:0901.2427 • Use MSTW2008 NNLO PDFs • Error prescription from PDF4LHC • Errors evaluated by jet bin • Further details on combinations: http://tevnphwg.fnal.gov Gavin Davies – IoP2011

  22. By Experiment • Exclusion by each experiment: • CDF: excludes SM Higgs for 158 < mH < 168 GeV • DØ: excludes SM Higgs for 163 < mH < 168 GeV Gavin Davies – IoP2011

  23. Tevatron SM Higgs excluded at 95% CL for 158 < mH < 173 GeV Expected exclusion at 95% CL 153 < mH < 179 GeV Gavin Davies – IoP2011

  24. Tevatron SM Higgs excluded at 99.5% CL for 162 < mH < 166 GeV Gavin Davies – IoP2011

  25. Combining Direct & Indirect Limits At 95% CL: Allowed region <140GeV Gfitter: combines direct and indirect constraints Gavin Davies – IoP2011

  26. DØ preliminary, 8.2fb-1 Higgs Beyond the SM… • Wide range of searches • MSSM, NMSSM, Fermiophobic, 4 Generations • Fermiophobic 124-202 GeV excluded World’s best limits Mhf > 113 GeV Gavin Davies – IoP2011

  27. SM Higgs Prospects • Ongoing programme of improvements • Expect exclusion over whole mass range Tevatron: Preliminary Higgs Projection Gavin Davies – IoP2011

  28. Conclusions • Tevatron and CDF/ DØexperiments continue to perform very well • Wealth of new results • Across many areas • High mass Higgs combination • Observed: 158 < mH < 173 GeV • Expected: 153 < mH < 179 GeV • Single experiment exclusion • Many new results soon • eg BSM Higgs combination, full mass SM Higgs combination • eg Updated W mass, Muon CP asymmetry Stay tuned: Tevatron at its best! Thank you Gavin Davies – IoP2011

  29. Backup slides Gavin Davies – IoP2011

  30. CDF and DØ Experiments • Both detectors extensively upgraded for Run IIa • New silicon vertex detector • New tracking system • Upgraded muon chambers • CDF: New plug calorimeter & ToF • DØ • New solenoid & preshowers • Run IIb: New inner tracking layer & L1 trigger Gavin Davies – IoP2011

  31. DØ Data Taking Gavin Davies – IoP2011

  32. Other ‘Top’ Results • eg t’ • eg spin-correlations NLO QCD: Gavin Davies – IoP2011

  33. FCNC Gavin Davies – IoP2011

  34. CP Muon Asymmetry • N++, N−− : number of events with two like-sign dimuons • n+, n− : number of muons with given charge See Guennadi Borissov’s talk on Thursday Gavin Davies – IoP2011

  35. Tevatron High Mass Combination With background subtraction Agreement between background model and data very good Gavin Davies – IoP2011

  36. CLs and CLs+b CLs = CLs+b/CLb CLs+b Same exclusion ranges as Bayesian approach Gavin Davies – IoP2011

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