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Top Quark mass measurement using J/psi in b-jet.

Introduction

  • Top쿼크의 질량을 측정하기 위하여 ttbar->W+b W- bbar -> llvv bj bj, dileptonic decay 채널에서의 b-jet의 붕괴가 J/psi로 붕괴되는 경우, J/psi로부터 생성된 dilepton과 같은 Top 쿼크로부터 나온 lepton을 이용하여 Top quark의 질량을 측정할 수 있을 것으로 기대하고 있다.

CMS Detector

Simulated samples

  • Signal and Backgroud sample
Name of the dataset # of Events Cross Section(pb) Etc.(S=Signal, B=Background) DAS Link etc.
TTJets_FullLeptMGDecays_8TeV-madgraph-tauola 12011428 26.54 S Link  
TTJets_SemiLeptMGDecays_8TeV-madgraph-tauola 31004465 110.778 B Link  
TTJets_HadronicMGDecays_8TeV-madgraph 10537444* + 31223821 115.564 B Link, Link2 Only link1 is used
DYJetsToLL? M10-50 7132223 907.3155 B Link  
DYJetsToLL? M-50 30459503 3503.71 B Link  
WJetsToLNu? 57709905 37509 B Link  
T_tW 497658 11.1773 B Link  
Tbar_tW 493460 11.1773 B Link  
WW 10000431 56 B Link  
WZ 10000283 33.6 B Link  
ZZ 9799908 7.6 B Link  

  • Inclusive mass samples
    • All sample's cross section is xxx
Name of the dataset # of Events Simulated Top quark mass
TTJets_mass161_5 5369214 161.5GeV/c^2
TTJets_mass163_5 5365348 163.5GeV/c^2
TTJets_mass166_5 4469095 166.5GeV/c^2
TTJets_mass169_5 5202817 169.5GeV/c^2
TTJets_mass175_5 5186494 175.5GeV/c^2
TTJets_mass178_5 4733483 178.5GeV/c^2
TTJets_mass181_5 5145140 181.5GeV/c^2
TTJets_mass184_5 5249525 184.5GeV/c^2

Object reconstruction

Isolated Muon

Isolated Electron

Jet

b-Jet

Data sample and event preselection

Dataset # of Events etc.

/DoubleMuParked/Run2012A-22Jan2013-v1/AOD 6432930  
/DoubleMuParked/Run2012B-22Jan2013-v1/AOD 29308627  
/DoubleMuParked/Run2012C-22Jan2013-v1/AOD 36820243  
/DoubleMuParked/Run2012D-22Jan2013-v1/AOD 38006513  
DoubleMu? Total 110568313  

/DoubleElectron/Run2012A-22Jan2013-v1/AOD 12964286  
/DoubleElectron/Run2012B-22Jan2013-v1/AOD 23571931  
/DoubleElectron/Run2012C-22Jan2013-v1/AOD 33843769  
/DoubleElectron/Run2012D-22Jan2013-v1/AOD 34526899  
DoubleElectron? Total 104906885  
/MuEG/Run2012A-22Jan2013-v1/AOD 2518137  
/MuEG/Run2012B-22Jan2013-v1/AOD 14776453  
/MuEG/Run2012C-22Jan2013-v1/AOD 20791905  
/MuEG/Run2012D-22Jan2013-v1/AOD 21978229  
MuEG? Total 60064724  

Background estimation

Systematic uncertainties

Reconstruction fo J/psi candidates

Secondary vertex

TMVA method

Comparision of different MC

Conclusions

Appendix

Reference

-- GunmoRyu - 12 Oct 2015

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Topic revision: r4 - 2015-10-14 - GunmoRyu
 
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