ttbar τ + jets:Update on QCD Estimation

William EdsonSUNY at Albany

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

New Event Selection VerificationCut Sig

EvtsFakes Sig Eff. Fake

RatioRej

Fact.Sig/

sqrt(Bkgd)

Sig/Sqrt(Sig

+Bkgd)

C5Lep Veto

9137 7177304

- - - 3.411 3.408

C6ntaus >

0

9137 1303893

1 0.1817 0.007007

8.002 7.974

C7njets

5051 365380 0.5528 0.2802 0.02501 8.356 8.299

C8MET

4104 36606 0.8125 0.1002 0.1380 21.45 20.34

C9MT

2995 18696 0.7298 0.5107 0.2195 21.90 20.34

C10bjet

2604 4151 0.8694 0.2220 0.7215 40.42 31.68

C12Trig

match

1480 531 0.5684 0.1279 4.904 64.23 33.00

MT Plots

Current Results No jvf applied:

Signal Fraction: 0.837897 ± 0.0775282 chi2 minimum: 47.3013 Efficiency: 1.3809x10-3

σ = 209.114 ± 19.349pb Using jvf in object selection and jvf_sf:

Signal Fraction: 0.824826 ± 0.0763352 chi2 minimum: 46.54513

Gauss Fit to Ensemble Test Mean: 0.781932 Sigma: 0.073487

Back-up

New Event Selection VerificationCut Sig

EvtsFakes Sig Eff. Fake

RatioRej

Fact.Sig/

sqrt(Bkgd)

Sig/Sqrt(Sig

+Bkgd)

C5Lep Veto

9088 7119872

- - - 3.406 3.404

C6ntaus >

0

9088 1292781

1 0.1816 0.00703 7.993 7.965

C7njets

5023 362609 0.5527 0.2805 0.02506 8.341 8.284

C8MET

4080 36434 0.8123 0.1005 0.1379 21.38 20.27

C9MT

2974 18563 0.7289 0.5095 0.2198 21.83 20.27

C10bjet

2585 4089 0.8692 0.2203 0.7273 40.43 31.64

C12Trig

match

1474 512 0.5702 0.1252 5.049 65.14 33.08

Systematic Values

Systematic Signal Fraction

σ(pb) Error

ISR/FSR baseline

0.815771 120.157σ not within Hi

and Low

ISR/FSRHi: 0.747423Low: 0.73338

146.232126.244

symmetrized± 9.994

JER 0.915222 228.389 ± 19.275

JRE 0.841604 210.381 ± 1.267

JESUp: 0.809931

Down: 0.726454

184.609199.827

symmetrized± 7.609

Highest pT bjet reconstruction Results for plot:

chi-square: 8.389 p-value: 0.8681 ndf: 14 chi/ndf: 0.5992

2nd highest pT bjet reconstruction

Results for plot: chi-square: 20.60 p-value: 0.1501 ndf: 15 chi/ndf: 1.373

Dijet reconstruction Results for plot:

chi-square: 4.581 p-value: 0.9497 ndf: 11 chi/ndf: 0.4165

Closest Top mass reconstruction

Results for plot: chi-square: 6.075 p-value: 0.8683 ndf: 11 chi/ndf: 0.5523

σi by First Derivative

22

i

22

i

22

i

2i

2

i

22

22

22

22

i

OBnσn(OB)NumDatanσ

n(Data)NumQCDnσ

n(QCD)Numsignσ

n(sig)Num

QCDNσN(QCD)

NumsigNσN(sig)NumOBNσ

N(OB)NumDataNσ

N(Data)Num

σ

iii

N(QCD)N(Remain)*frac(QCD)

n(QCD)Num

N(sig)N(Remain)*frac(sig)

n(sig)Num

N(QCD)n(QCD)*frac(QCD)*N(Remain)

N(QCD)Num

N(sig)n(sig)*frac(sig)*N(Remain)

N(sig)Num

D)binfrac(QC*frac(QCD)g)binfrac(si*g)fracsig(siN(OB)Num

D)binfrac(QC*frac(QCD)g)binfrac(si*g)fracsig(siN(Data)

Num

i

i

2i

2i

ii

ii

1n(Data)

Num

i

1

n(OB)Num

i

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