searches for h→bb at dØ

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Searches for Hbb at D. Satish Desai - Fermilab on behalf of the D Collaboration 36th International Conference on High Energy Physics Melbourne, Australia, 2012. As of Last Week. M H < 152 GeV (indirect constraints) 122 < M H < 127 GeV (searches). The Search Strategy. Main Decay: Hbb. - PowerPoint PPT Presentation

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  • Searches for Hbb at DSatish Desai - Fermilabon behalf of the D Collaboration 36th International Conference on High Energy PhysicsMelbourne, Australia, 2012

  • As of Last WeekMH < 152 GeV (indirect constraints)122 < MH < 127 GeV (searches)

  • The Search StrategyMain Decay: Hbb

  • The Search StrategyMain Decay: Hbb

  • The Search StrategyMain Decay: Hbb

  • Search IngredientsMaximize acceptance and efficiencyEfficient b-taggingSplit into subsamples with different puritiesMultivariate Techniquesllbblbbbb

  • Increasing AcceptanceWH Analysisllbb Analysis

  • More b-tagging CategoriesWH Analysis

    S/BTight One Tag1/1600Loose Two Tag1/1400Medium Two Tag1/360Tight Two Tag1/200

  • More b-tagging CategoriesWH Analysis

    S/BTight One Tag1/1600Loose Two Tag1/1400Medium Two Tag1/360Tight Two Tag1/200

  • Targeting TopRemove 45% of backgroundKeep 94% of signalllbb AnalysisStill used asextra sample

  • Multivariate Techniquesvvbb Analysisvvbb AnalysisWH AnalysisMore optimal

  • Validation with DibosonsSee talk by B. Penning

  • ResultsOverall sensitivityimproves by 10-15%

  • The Log Likelihood RatioTest statistic used for CLs MethodLog likelihood ratio acts like 2 of fits to modelsBased on Poisson likelihoods for two hypotheses:signal+backgroundbackground onlySeparation betweenpoints acts like 2of fits to models

  • SummaryTevatron sensitivity to Hbb complements LHC resultsEvidence for VZX+bb used as a proving ground for Hbb searchModest excess for MH>120 GeVSee additional Tevatron Higgs talks at this conferenceFinalizing results nowhttp://www-d0.fnal.gov/Run2Physics/WWW/results/higgs.htm

  • Searching through the years20082009200720102011Spring 2012

  • Results for ZHbb

  • Results for ZHllbb

  • Results for WHlbb

  • S/B DistributionsSpring 2012Spring 2012Summer 2012Summer 2012

  • Accumulated SignalSpring 2012Spring 2012Summer 2012Summer 2012