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Update on QCD Estimation and Intra-PDF Uncertainty Results by William Edson

This document presents an update on the estimation of QCD (Quantum Chromodynamics) and discusses the results of the Intra-PDF (Parton Distribution Function) uncertainty analysis. It includes comparisons across different PDF sets including CT10, MSTW, and NNPDF, summarizing final uncertainties associated with each. The study involves various MC (Monte Carlo) generators and incorporates new event selection verification techniques while providing detailed results from ensemble fits and Chi-squared analyses to improve accuracy in event classification.

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Update on QCD Estimation and Intra-PDF Uncertainty Results by William Edson

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

  2. Intra-PDF Uncertainty Results • CT10: • ± 2.32093 • MSTW: • + 1.29293 / - 1.38225 • NNPDF: • ± 1.20644

  3. Envelope Results Therefore the final uncertainty is equivalent to the CT10 Intra Unc: ± 2.32093

  4. Fit Selection Results • Final Result:

  5. Back-up

  6. QCD Bin/Range Range increases/decreases in steps of 20GeV Bin amount increases/decreases in steps of 5

  7. MC Generator 1.1)fullsim mc11c POWHEG+fPythia sample 117050 (SYST_Full_117050) and MC@NLO+fHerwig sample 105200 (MC@NLO(105200)) 1.2)fullsim mc11c POWHEG+fPythia sample 117050 (SYST_Full_117050) and the fullsim mc11c ALPGEN+HERWIG samples (AlpHerwig(baseline)) 1.3) AtlFast2 mc11b POWHEG+fPythia sample 117050 (SYST_AtF_117050) POWHEG+fHerwig sample 105860 (SYST_AtF_105860)

  8. Mean Values of Ensemble Fits

  9. Y(0): -0.127757 ± 0.00142161 Slope: 1.18358 ± 0.00252649 Chi2: 34.4482 NDF: 8997 Linearity Testto All Values

  10. Adjust Range for Linear Fit?

  11. Top Mass

  12. MC Tau Plots MC Tau Children Count MC Tau Count MC Tau Children pdgID LeptonicpdgID values: e → 11, μ → 13, τ → 15

  13. MT Signal vs Control vs MC Backgrounds Samples Normalized to Own Integrals Samples Normalized to Sum of Integrals

  14. Fits/Hists for Ensemble Tests

  15. Cutflow • C0: GRL • C1: Trigger • C2: Primary vertex with ntracks > 4 • C3: Electron/muon overlap • C4: Jet cleaning • C5: Lepton Veto • C6: tau n ≥ 1 • C7: njets >= 4 with eta < 2.5 and |jvf| > 0.75 • C8: MET > 60GeV • C9: MT < 80GeV • C10: >= 1 bjet • C11: Trigger matched tau n ≥ 1 and pT >= 40GeV • C12: MC tau object match

  16. 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

  17. 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

  18. Highest pTbjet reconstruction • Results for plot: • chi-square: 9.818 • p-value: 0.7753 • ndf: 14 • chi/ndf: 0.7012

  19. 2nd Highest pTbjet reconstruction • Results for plot: • chi-square: 13.66 • p-value: 0.5517 • ndf: 15 • chi/ndf: 0.9107

  20. Dijet Mass reconstruction • Results for plot: • chi-square: 15.47 • p-value: 0.6297 • ndf: 18 • chi/ndf: 0.8594

  21. MET • Results for plot: • chi-square: 15.87 • p-value: 0.1971 • ndf: 12 • chi/ndf: 1.323

  22. Closest pTbjet reconstruction • Results for plot: • chi-square: 14.39 • p-value: 0.2123 • ndf: 11 • chi/ndf: 1.308

  23. New Event Selection Verification (Only uses MC so Excludes QCD)

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