ttbar τ + jets:Update on QCD Estimation

William EdsonSUNY at Albany

No MET Fit Selection Results for Fit:

Signal Fraction: 0.847182±0.0634855

Chi2: 46.8597 Meas. Used: 57 σ:

208.927±15.656pb Ensemble Results:

Mean: 0.760173±0.00269476

chi2: 11.5963

Using Serban’s Suggestion of Randomizing Full Data Histogram

mean: 0.584753±0.00156137 sigma: 0.0490295Chi2: 8.17953 NDF: 12

Using Brad’s Suggestion of Using Random Filled TFunction as QCD Template During Fitting Process

mean: 0.944558±0.00105631 sigma: 0.0327505Chi2: 14.6119 NDF: 7

Comparison of Ensemble Data to Real Data

Highest pT bjet Second pT bjet

Comparison of Ensemble Data to Real Data

Dijet MET

Comparison of Ensemble Data to Real Data

Closest Top Mass Reconstruction

Back-up

Histograms Used in Fit Comparisons

MET

Dijet Mass

Histograms Used in Fit ComparisonsHighest pT bjet Reconstruction

2nd Highest pT bjet ReconstructionThe other background histograms titled incorrectly due to error in the analysis code, has been corrected.

Fit With Only 1 Histogram Highest:

Signal Fraction: 0.796408±0.130703 Chi2: 15.64128

2nd bjet: Signal Fraction: 0.806464±0.101722 Chi2: 19.81387

Dijet: Signal Fraction: 0.941796±0.0986423 Chi2: 10.4168

MET Signal Fraction: 0.620279±0.044591 Chi2: 20.35018

New Fits for Ensemble Tests

Cutflow C0: GRL C1: Trigger C2: Primary vertex with ntracks > 4 C3: Electron/muon overlap, larVeto 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

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 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

Highest pT bjet reconstruction Results for plot:

chi-square: 18.798 p-value: 0.4044 ndf: 18 chi/ndf: 1.044

2nd Highest pT bjet reconstruction

Results for plot: chi-square: 20.82 p-value: 0.2346 ndf: 17 chi/ndf: 1.225

Dijet Mass reconstruction Results for plot:

chi-square: 12.06 p-value: 0.8829 ndf: 19 chi/ndf: 0.6347

Closest pT bjet reconstruction Results for plot:

chi-square: 8.373 p-value: 0.93697 ndf: 16 chi/ndf: 0.5233

New Event Selection VerificationCut Sig

EvtsFakes Sig Eff. Fake

RatioRej

Fact.Sig/

sqrt(Bkgd)

Sig/Sqrt(Sig

+Bkgd)

C5Lep Veto

9137 7180594

- - - 3.410 3.408

C6ntaus >

0

9137 1304359

1 0.1817 0.007004

8.000 7.974

C7njets

5051 365445 0.5528 0.2802 0.02500 8.355 8.298

C8MET

4104 36622 0.8125 0.1002 0.1379 21.45 20.34

C9MT

2995 18708 0.7298 0.5108 0.2194 21.90 20.33

C10bjet

2604 4159 0.8694 0.2223 0.7201 40.38 31.66

C12Trig

match

1480 536 0.5684 0.1289 4.858 63.93 32.96

Linear Fit To Mean Values

y(0): 0.0121648±0.00477388 slope: 0.927763±0.00910238chi2: 7.63631 NDF: 7

Linear Fit To All Fractions

y(0): 0.00762894±0.00158121 slope: 0.935856±0.00280988chi2: 42.6259 NDF: 8998

MT Plots

Function Fits of QCD Templates

Mean: 171.283 ± 5.986

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