ttbar τ + jets:Update on QCD Estimation

William EdsonSUNY at Albany

New Event Selection Verification

Cut Sig Evts

Fakes Sig Eff. Fake Ratio

Rej Fact.

Sig/sqrt(Bkg

d)

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

Single Bin Tests for Variance

Using the first derivative: Calculated variance (σi): 8.42421 Gaussian fit sigma: 8.48931 Webpage crosscheck*: 8.4

Results imply using first derivatives to determine σi to be consistent

Webpage: http://www.colby.edu/chemistry/PChem/scripts/error.html

Current Results

Signal Fraction: 0.837897 ± 0.0775282 chi2 minimum: 47.3013

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

Back-up

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

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) Y

g)binfrac(si*N(Remain)*frac(Sig) X

)σ(n(OB)σ(Y))σ(X))σ(n(Data)σ

σi by First Derivative

2

2

i

2

2

i

2

2

i

2i

2

i

2

2

2

2

2

2

2

2

i

OBnσn(OB)

NumDatanσ

n(Data)

NumQCDnσ

n(QCD)

Numsignσ

n(sig)

Num

QCDNσN(QCD)

NumsigNσ

N(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

N

NEff

gen

rec

N

NAcc

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