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 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

Fractional Error Addition

Signal Fraction: 0.91632 ± 0.167012 Minimum: 3.76511

j jX

)( σ j

i

X

Gaus Mean: 0.933425 Sigma: 0.0439541

By Operation Error Addition

Signal Fraction: 0.897266 ± 0.141041 Minimum: 8.56055

Gaus Mean: 0.970150 Sigma: 0.0389473

For details see backup, slide 11

First Derivative Error Addition

Signal Fraction: 0.505793 ± 0.135081 Minimum: 29.0232

Gaus Mean: 0.721834 Sigma: 0.0662957

For details see backup, slide 12

Event Selection Verification

Cut Sig Evts

Fakes Sig Eff. Fake Ratio

Rej Fact.

Sig/sqrt(Bkg

d)

Sig/Sqrt(Sig

+Bkgd)

C5Lep Veto

9224 1303424

- - - 8.07935 8.0509

C6njets

5051 388986 0.5476 0.2984 0.02371 8.09861 8.0465

C7MET

4105 34714 0.8127 0.08924 0.1455 22.0324 20.8349

C8MT

2679 15504 0.6526 0.4466 0.2648 21.5155 19.8674

C9SumET

1172 3838 0.4375 0.2475 0.6980 18.918 16.5580

C10bjet

1005 496 0.8575 0.1292 2.3629 45.1258 25.9403

C12Trig

match

456 81 0.4537 0.1633 12.4074 50.6667 19.6779

MET > 60 GeV and SumET < 500 GeV

MT < 70 GeV

Back-up

σi by Operation Details

22

i

iii

22

2

i

i

2

i

i

2i

222ii

N(sig)σ(N(sig))

n(sig)n(sig)σ*g)binfrac(si)sig)σ(binfrac(

(N(OB)))((N(Data)))())σ(N(Remain

g)binfrac(si)sig)σ(binfrac(

N(Remain)))σ(N(Remain*X σ(X)

D)binfrac(QC*N(Remain)*frac(QCD) Yg)binfrac(si*N(Remain)*frac(Sig) X

)σ(n(OB)σ(Y))σ(X))σ(n(Data)σ

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

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