TWiki> Main Web>TWikiUsers>PedroSilva>PedroVtbMeasurementStudies>GeneralHFCProbes (2009-12-07, PedroSilva) EditAttachPDF

Probing the top quark branching fraction

Generic approach to probe the top quark branching fraction in top pair events produced in proton-proton collisions

Outline

Who

  • Pedro Silva
  • Michele Gallinaro
  • Joćo Varela

Tasks

  • Describe phenomenogically how the top quark brancing fraction can be probed in $t\bar{t}$ events
  • Use generator level results

CS

  • Checkout from cvs: cvs -d:local:/lip-sw/cmssw/results/ co top/TopDecay
  • Compile: make
  • Check in changes: cvs ci -m'your comment'

Note

  • Latest version: pdf

Samples and selection

Samples : The official CMS samples for the Summer08/Winter09 productions are used for this study:

Process Dataset Cross section
$t\bar{t}$ /TTJets-madgraph/Fall08_IDEAL_V9_v2/GEN-SIM-RECO 414 pb
/TauolaTTbar/Summer08_IDEAL_V9_v2/GEN-SIM-RECO
Single top /SingleTop_sChannel/Summer08_IDEAL_V9_v1/GEN-SIM-RECO 5 pb
/SingleTop_tChannel/Summer08_IDEAL_V11_redigi_v3/GEN-SIM-RECO 130 pb
/SingleTop_tWChannel/Summer08_IDEAL_V11_redigi_v3/GEN-SIM-RECO 29 pb
W/Z+jets /Wjets-madgraph/Winter09_IDEAL_V11_FastSim_v1/GEN-SIM-DIGI-RECO 40 nb
/Zjets-madgraph/Winter09_IDEAL_V11_FastSim_v1/GEN-SIM-DIGI-RECO 3.54 nb
Di-boson /WW/Winter09_IDEAL_V12_FastSim_v1/GEN-SIM-DIGI-RECO 74 pb
/WZ/Winter09_IDEAL_V12_FastSim_v1/GEN-SIM-DIGI-RECO 32 pb
/ZZ/Winter09_IDEAL_V12_FastSim_v1/GEN-SIM-DIGI-RECO 10.5 pb
QCD /QCD_EMenriched_Pt20to30/Summer08_IDEAL_V11_redigi_v2/GEN-SIM-RECO 3.2 $\mu b$
/QCD_EMenriched_Pt30to80/Summer08_IDEAL_V11_redigi_v2/GEN-SIM-RECO 4.7 $\mu b$
/QCD_EMenriched_Pt80to170/Summer08_IDEAL_V9_v1/GEN-SIM-RECO 0.285 $\mu b$
/InclusiveMuPt15/Summer08_IDEAL_V9_v1/GEN-SIM-RECO 0.1216749 $\mu b$

Events : The events are analyzed with generator level information, i.e.:

  • Particles : genParticles - the generator level particle collection;
  • Jets : sisCone5GenJets (kt4GenJets) - jets built from status 1 particles with the SIS-cone ($k_T$) algorithm;
  • Jets to Partons matches : sisConeFlavourByRef (ktFlavourByRef)- correspondences between the partons found in the particles collection and each jet clustered by the SIS-cone ($k_T$) algorithm;

Selection : The events are selected as follows:

  • "Trigger" : 1 $e/\mu$ with $p_T>$15 GeV/c; $| \eta |<$3;
  • $\geq$ 2 leptons : $p_T>$20 GeV/c ; $| \eta |<$2.5; $|d_0|<$ 400 $\mu m$; $I_{track}=\sum_{0.07<\Delta R<0.4} p_{T}^{i} /p_{T} < 0.1$ (for charged particles with $p_{T}>$0.5 GeV/c); $\Delta R(lepton)>0.3$;
  • Dilepton pair : leading pair in $p_T$ with $|M_{ll}-M_Z|<5 GeV/c^2$;
  • $\geq$ 2 jets : $p_T>$30 GeV/c ; $| \eta |<$2.5; $\Delta R(selected~lepton)>0.3$; $N_{constituents}(E_T>1~GeV)>2$ and $N_{tracks}(p_T>0.5~GeV/c)>2$
  • $\cancel{E}_T$ : $|\sum_{|\eta|<2.5} \vec{p}_T(\nu_i) |>$ 30 GeV
  • Opposite sign charged leptons

Control : The selection control plots are shown below. The quantities are plotted only if the event has survived up to a given step.

Leptons
Dileptons
Jets
$\bf \cancel{E}_T$
Op. sign

Event yields : The event yields for $\mathcal{L}=100~pb^{-1}$ are shown below.

-- PedroSilva - 04-Nov-2009

Attachments Attachments
Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng CutFlow.png r1 manage 66.9 K 2009-11-18 - 19:28 PedroSilva  
PNGpng Dileptons_charge.png r1 manage 9.5 K 2009-11-18 - 16:52 PedroSilva  
PNGpng Dileptons_minv.png r1 manage 13.5 K 2009-11-18 - 16:52 PedroSilva  
PNGpng Dileptons_pt.png r1 manage 12.8 K 2009-11-18 - 16:52 PedroSilva  
PNGpng Jets_constituents.png r1 manage 10.2 K 2009-11-18 - 16:53 PedroSilva  
PNGpng Jets_eta.png r1 manage 7.8 K 2009-11-18 - 16:53 PedroSilva  
PNGpng Jets_minDR2lepton.png r1 manage 9.0 K 2009-11-18 - 16:53 PedroSilva  
PNGpng Jets_ntracks.png r1 manage 10.0 K 2009-11-18 - 16:53 PedroSilva  
PNGpng Jets_pt.png r1 manage 12.7 K 2009-11-18 - 16:51 PedroSilva  
PNGpng Lepton_chargedreliso.png r1 manage 11.5 K 2009-11-18 - 16:51 PedroSilva  
PNGpng Lepton_d0.png r1 manage 11.2 K 2009-11-18 - 16:51 PedroSilva  
PNGpng Lepton_eta.png r1 manage 8.7 K 2009-11-18 - 16:51 PedroSilva  
PNGpng Lepton_minDR2lepton.png r1 manage 11.3 K 2009-11-18 - 16:50 PedroSilva  
PNGpng Lepton_pt.png r1 manage 13.8 K 2009-11-18 - 16:50 PedroSilva  
Texttxt ListBehind_08.11.2009.txt r1 manage 11.2 K 2009-11-19 - 13:55 PedroSilva  
PNGpng MET.png r1 manage 11.9 K 2009-11-18 - 16:45 PedroSilva  
PDFpdf TopDecay.pdf r1 manage 284.8 K 2009-12-07 - 22:38 PedroSilva  
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