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Update on QCD Estimation in ttbar + Jets Analysis by William Edson, SUNY Albany

This presentation outlines the latest findings on the QCD estimation for the ttbar + jets process. Utilizing chi-squared minimization methods, we analyze the total number of events and the signal fraction across different analysis runs. The study incorporates statistical and systematic uncertainties, with data obtained from various MC templates and background sources. Key results from Run 1 highlight signal fractions and chi-squared values, indicating significant insights into jet reconstruction and background interaction, crucial for enhancing our understanding of QCD processes in high-energy physics contexts.

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Update on QCD Estimation in ttbar + Jets Analysis by William Edson, SUNY Albany

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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 by adding in quadrature • bin error: • data • signal, MC • QCD template • other backgrounds, MC • statistical error: • data: signal region (times 2) • data: background region • other backgrounds, MC (times 2) • signal, MC • signal and other backgrounds combined, MC: background region

  4. Results Rerunning Analysis Using Old Code • Run 1: • chi-squared: 26.75 • signal fraction: 0.7744 +/- 0.0742 • Rescale signal MC in all regions and rerun: • chi-squared: 25.51 • signal fraction: 0.7747+/- 0.0702

  5. Highest pTbjet reconstruction • Chi2: 14.46 • NDF: 9 • Chi2/NDF: 1.607

  6. 2nd highest pTbjet reconstruction • Chi2: 7.534 • NDF: 9 • Chi2/NDF: 0.8371

  7. Dijet reconstruction • Chi2: 7.524 • NDF: 11 • Chi2/NDF: 0.6840

  8. Closest Top mass reconstruction • Chi2: 11.70 • NDF: 8 • Chi2/NDF: 1.463

  9. Oddity

  10. Back-up

  11. Results • Run 1: • chi-squared: 31.78 • signal fraction: 0.7415 +/- 0.0823 • Rescale signal MC in all regions and rerun: • chi-squared: 30.94 • signal fraction: 0.7400+/- 0.0792

  12. Results • Run 1: • chi-squared: 4.541 • signal fraction: 0.9891+/- 0.1460 • Rescale signal MC in all regions and rerun: • chi-squared: 3.905 • signal fraction: 0.9787+/- 0.1233

  13. Highest pTbjet reconstruction June 6 Old Code

  14. 2nd highest pTbjet reconstruction June 6 Old Code

  15. Dijet reconstruction June 6 Old Code

  16. Closest Top mass reconstruction June 6 Old Code

  17. 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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