First measurement of the ttbar production cross section in the dilepton channel with tau leptons in the final state in pp collisions at sqrt(s)=7TeV

Abstract

We present a measurement of the ttbar production cross section in dilepton events with one muon and one hadronically decaying tau lepton from the decay ttbar → ( mu + nu_mu) + ( tau_h + nu_tau) + bbbar. This is the first measurement of the ttbar cross section explicitly including tau leptons in proton-proton collisions at sqrt(s)=7TeV. The data sample corresponds to an integrated luminosity of 1.09 /fb collected by the CMS detector. The measured value sigma = 148.7 23.6 ( stat.) 26.0( syst. ) 8.9 (lumi.) \pb is consistent with predictions from the standard model.

Detailed record in (to be added)

Approved Results from TOP-11-006

Result Abbreviated Caption
Measured ttbar production cross section in dilepton events with one muon and one hadronically decaying tau lepton with an integrated luminosity of 1.09 /fb collected by the CMS detector

Approved Plots from TOP-11-006 ( click on plot to get .pdf )

Figure Abbreviated Caption
Muon pt distribution in events with at least one muon and at least three jets (two jets with pt>30GeV/c and one jet with pt>20GeV/c). Distributions obtained from data (points) are compared with the MC samples. PNG

Jet pt distribution in events with at least one muon and at least three jets (two jets with pt>30GeV/c and one jet with pt>20GeV/c). Distributions obtained from data (points) are compared with the MC samples. PNG

Jet multiplicity distribution in events with one identified charged muon and at least three jets (two jets with pt>30GeV/c and one jet with pt>20GeV/c).PNG

Missing Et distribution in events with one identified charged muon and at least three jets (two jets with pt>30GeV/c and one jet with pt>20GeV/c).PNG

The b-tagging jet multiplicity for events with one muon, at least 3 jets (two jets with pt>30GeV/c and one jet with pt>20GeV/c and MET>40GeV.PNG

The tau pt distribution of selected events.PNG

The tau eta distribution of selected events.PNG

Reconstructed top quark mass distribution for the tau dilepton candidate events after the full event selection. Distributions obtained from data (points) are compared directly with simulation.PNG

Inclusive jet pt distribution for mu+>=3 jet events after MET cut and with at least two jets with pt>30GeV/c and at least one jet with pt>20GeV/c (at least one jet with pt>30GeV/c is b-tagged ).PNG

Tau Fake rate distribution as function of jet pt obtained from QCD multijet samples compared for data and MC events.PNG

Tables from TOP-11-006 ( click on plot to get .png )

Result Abbreviated Caption
table1.png Sources of systematic uncertainties (in %) in the cross section measurement.

table2_b.png Number of expected events for signal and backgrounds. The background from "tau fakes" is estimated from data, while the other backgrounds are estimated from simulation. Statistical and systematic uncertainties are shown. The statistical uncertainties are due to MC statistics, while for the tau-fakes the statistical uncertainties are due to the fake rate in the data.

-- NunoAlmeida - 17-Jul-2011

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PNGpng ljets_eta_m_3j.png r1 manage 14.0 K 2011-07-18 - 12:14 UnknownUser  
PDFpdf ljets_pt_m_3j.pdf r1 manage 24.8 K 2011-07-20 - 17:18 UnknownUser  
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PNGpng mjets_pt_t_1t.png r2 r1 manage 18.1 K 2011-07-19 - 20:17 UnknownUser  
PDFpdf mjets_wjets.pdf r2 r1 manage 23.7 K 2011-07-19 - 21:36 ArunaNayak  
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PNGpng table1.png r3 r2 r1 manage 53.5 K 2011-07-25 - 12:48 MicheleGallinaro  
PNGpng table2.png r1 manage 47.1 K 2011-07-21 - 13:11 UnknownUser  
PNGpng table2_b.png r1 manage 47.1 K 2011-07-21 - 13:14 UnknownUser  
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Topic revision: r11 - 2011-10-10 - FrankPeterSchilling
 
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