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Published byIrma Mills Modified over 8 years ago
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Z BF using hadronic events Silke Duensing Aug 8th, 2003
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Decay and Identification hadronic decays No L1 track trigger Use leptons Choose for muon type type
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Z hadronic
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hadronic Reconstruction Understanding the Tau –Reconstruction
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hadronic Reconstruction Understanding the Tau oTrack matching Tracks, pT > 1.5 in 0.5 cone 2nd, 3rd track: consider invariant mass + charge 3 prong tracking efficiency: unknown 1 prong as 3 prong: pickup tracks 3 prong as 1 prong: inefficiency
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hadronic Selection ( -type)
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Signal sample and Trigger Select had candidates: Clean, high pT muon Muon is isolated –Cut on max(E T Halo + p T trk in 0.5) –Used cut is used in optimization of cut Require with uncorrected ET > 10 GeV MU_TAU10_L2M0 Trigger contains muon terms at L1 and L2 L1: + 1 trigger tower (0.2x0.2 in ) above 5 GeV CJT -specific term at L3 a L3 track > 5 GeV Require a match of tau to trigger objects
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hadronic L L rigger Understanding the Tau –Reconstruction –Separation into Types –Selection using Square Cuts –Trigger Efficiency Not many taus in data Thus use QCD jets that are tau-like Checked “box”-result with profile weighting
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Towards the Z had cross-section Muon+Tau Efficiencies Isolation Trigger Efficiency Background –From: QCD W Z ->opposite sign! WW tt same chg = opp chg small, from MC Reject w. cuts
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Backgrounds (I) –From: QCD W Z ->opposite sign! WW tt same chg = opp chg Reject w. cuts Additional ( > 0.5) loose mu (in fid region) Isolated track w. pT > 15 (in non-fid region) Use Z in data to get # of remaining events in signal
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Background (II) –From: QCD W Z ->opposite sign! WW tt same chg = opp chg small, from MC Reject w. cuts Use MC muon, account for data efficiencies, use tau + electron efficiencies
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Backgrounds (III) –From: QCD W Z ->opposite sign! WW tt same chg = opp chg small, from MC Reject w. cuts
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The candidates in the case …are expected to be back-to back …and have an invariant mass of the muon and tau 10<m<60 GeV
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Putting the pieces together
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Systematics on selection Three sources of systemtatics in selection: –JES when cut on ET/pT –Tracking efficiency for track isolation –MC modeling for shape cut JES: vary E by 10% Tracking isolation –Compare Z MC and data Shape cuts: –Look at os – ss events, –Correct with CM efficiency constant?
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Systematic check: electrons as taus For main seletion: Take electron factor from MC Check with cross section Including electron cut : fractor 1.3
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Isolated muon Muon is isolated –Muons from Z are like muons from Z –Signal: use Z mm –Background: events with low MET –Used cut is used in optimized
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hadronic L rigger Understanding the Tau –Reconstruction –Separation into Types –Selection using Square Cuts –Trigger Efficiency Not many taus in data Thus use QCD jets that are tau-like
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