Liu Zhijun Liang July 25 2011 Data Driven Decomposition Method for MET acceptance 1 Motivation 2 Data Zee Bunch pileup MET The Idea from Stefan etc Use a data driven method to calculate MET acceptance for W ID: 579782
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Slide1
Dong Liu, Zhijun LiangJuly 25, 2011
Data Driven Decomposition Method for MET acceptance
1Slide2
Motivation2
Data Zee
Bunch
pile-up
METSlide3
The Idea --from Stefan etc.Use a data driven method to calculate MET acceptance for W/Wgamma analysisMET = Real + FakeFake MET extracted from the Z Events using Decomposition method. Characterized by the boson pt
and the event SumEt:Perpendicular to boson
Pt
--random source ->
SumEt
Parallel to boson
Pt
--Hadron energy scale ->Boson pt --random source ->SumEt
3Slide4
Fake MET In Z eventsParallel MET Perpendicular MET4Slide5
Bias vs Z_pt5
Perpendicular
MET
Parallel
MET Slide6
MET Resolution vs SumETSumET: leptons/photons subtracted6Slide7
Bunch dependence7Zee events:
Data
Data
MC
MCSlide8
Bunch dependence8Data Zee events:Slide9
Bias from W/Wgamma9
Wenu
Wgamma
Wgamma
FSR
Wgamma
ISR Slide10
MET calculation
Parallel MET
Perpendicular
MET
10Slide11
Fake MET11Zee Wenu
Red :
MET_Truth-MET_reco
Black:Smearing
function in
previous
page Slide12
MET12Wenu WgammaSlide13
Acceptance13
Acceptance
Uncertainty
(stat.)
Non_Closure
Wgamma
Truth MET
69.08%
0.09%
Reco
MET
71.05%
0.08%
MC Smearing
70.94%
0.08%
-0.15%
Data Smearing
70.96%
0.07%
-0.12%
Acceptance
Uncertainty
(stat.)
Non_Closure
Wenu
Truth MET
70.27%
0.06%
Reco
MET
70.86%
0.06%
MC Smearing
71.35%
0.07%
0.68%
Data Smearing
71.31%
0.07%
0.63%Slide14
Systematic Uncertainties Calculation:statistical uncertainties ->plenty eventsDifference between in Z and W(gamma) eventsBackground in Z events ->smallIncorrectly determined SumEt Difference between Reconstruction MET and new MET -- Non_Closure test
14Slide15
Sumet15Wenu WgammaSlide16
Sumet +-10%16Wenu WgammaSlide17
Uncertainty due to sumet17Sumet were shifted by 10%
Acceptance
Uncertainty
Wgamma
sumet
-10%
MC Smearing
70.79%
-0.22%
Data Smearing
70.76%
-0.28%
sumet
+10%
MC Smearing
71.09%
0.21%
Data Smearing
71.07%
0.16%
Acceptance
Uncertainty
Wenu
sumet
-10%
MC Smearing
71.20%
-0.20%
Data Smearing
71.18%
-0.17%
sumet +10%
MC Smearing
71.47%
0.17%
Data Smearing
71.44%
0.18%Slide18
Conclusion18Could calculate the MET acceptance using Data Driven Decomposition MethodUncertainties
Wenu
Wgamma
Non_Closure
0.7%
0.2%
Sumet
shift
0.2%
0.3%
Difference Between Z/W(
Wgamma
)
?
?
other source
?
?