Post on 21-Mar-2016
description
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