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
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