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ttbar  τ + jets : Update on QCD Estimation

ttbar  τ + jets : Update on QCD Estimation. William Edson SUNY at Albany. Chi-squared minimization. Equation: N(x): total number of events of type x for distribution n(x) i : number of events in bin of type x frac (Sig): fraction of N(Remain) expected to be Signal

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ttbar  τ + jets : Update on QCD Estimation

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  1. ttbarτ + jets:Update on QCD Estimation William Edson SUNY at Albany

  2. Chi-squared minimization • Equation: • N(x): total number of events of type x for distribution • n(x)i: number of events in bin of type x • frac(Sig): fraction of N(Remain) expected to be Signal • binfrac(x)i: fraction of events in bin of type x expected from MC or template • σi: uncertainty in bin i

  3. Chi-squared minimization cont. • σi determined using factors for: • bin error: • data • signal, MC • QCD template • other backgrounds, MC • statistical error: • data: signal region • other backgrounds, MC • signal, MC • QCD template (uncertainty of background region data and all MC background region carried through via default SumW2

  4. Fractional Error Addition Signal Fraction: 0.91632 ± 0.167012 Minimum: 3.76511 Gaus Mean: 0.933425 Sigma: 0.0439541

  5. By Operation Error Addition For details see backup, slide 11 Signal Fraction: 0.897266 ± 0.141041 Minimum: 8.56055 Gaus Mean: 0.970150 Sigma: 0.0389473

  6. First Derivative Error Addition For details see backup, slide 12 Signal Fraction: 0.505793 ± 0.135081 Minimum: 29.0232 Gaus Mean: 0.721834 Sigma: 0.0662957

  7. Event Selection Verification

  8. MET > 60 GeV and SumET < 500 GeV

  9. MT < 70 GeV

  10. Back-up

  11. σi by Operation Details

  12. σi by First Derivative

  13. Function Fits of QCD Templates Mean: 171.283 ± 5.986

  14. Proceeding Acceptance and Efficiency Work • Efficiency: Limiting to events in 105200 sample satisfying: • contain truth matched taus • single prong • muonVeto and eleBDTMedium == 0 • calo-seeded taus • Acceptance: Using all MC types • Nrec: MC events passing entire cutflow • Ngen: 105200 events using mc and trueTau branch information matched to single prong, BDTJetScore > 0.7 taus

  15. Cutflow • C0: GRL • C1: Trigger • C2: Primary vertex with ntracks > 4 • C3: Electron/muon overlap, larVeto • C4: Jet cleaning • C5: Lepton Veto • C6: njets >= 4 with eta < 2.5 and |jvf| > 0.75 • C7: MET > 60GeV • C8: MT < 70GeV • C9: Sum ET < 500GeV • C10: >= 1 bjet • C11: Tau n ≥ 1, BDTScore > 0.7 • C12: Trigger matched tau n ≥ 1 and pT >= 40GeV • C13: MC tau object match

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