ttbar τ + jets:Update on QCD Estimation

William EdsonSUNY 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 binfrac(x)i: fraction of events in bin of type x

expected from MC or template σi: uncertainty in bin i

2

i

iiii2

σ)n(OB)D)binfrac(QC*N(Remain)*frac(QCD)g)binfrac(si*N(Remain)*(frac(Sig)n(Data)χ

N(OB) - N(Data) N(Remain)

frac(Sig) - 1 frac(QCD)

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

Results Chi-square: 3.747 signal fraction: 0.91933 +/- 0.157592 signal fraction for all data: 0.819601

Ensemble tests with result signal fraction

Results with Gaussian Fit Associated Errors

Mean: 0.764889 +/- 0.002659 Sigma: 0.0805555 +/- 0.0020661

Linear Fit with Signal Fraction from 0.1 - 0.8

y(0): -0.00998677 +/- 0.05173513slope: 0.912698 +/- 0.1009633

Back-up

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

start

pass

NN

Eff gen

rec

NNAcc

Highest pT bjet reconstruction Results for plot:

chi-square: 7.341 p-value: 0.7709 ndf: 11 chi/ndf: 0.6674

2nd highest pT bjet reconstruction

Results for plot: chi-square: 13.76 p-value: 0.3166 ndf: 12 chi/ndf: 1.147

Dijet reconstruction Results for plot:

chi-square: 6.133 p-value: 0.8643 ndf: 11 chi/ndf: 0.5575

Closest Top mass reconstruction

Results for plot: chi-square: 5.342 p-value: 0.8035 ndf: 9 chi/ndf: 0.5936

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