# 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
Sources of systematic uncertainties (in %) in the cross section measurement.

 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

Topic attachments
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pdf ljets_eta_m_3j.pdf r2 r1 manage 24.8 K 2011-07-19 - 20:36 UnknownUser
png ljets_eta_m_3j.png r1 manage 14.0 K 2011-07-18 - 12:14 UnknownUser
pdf ljets_pt_m_3j.pdf r1 manage 24.8 K 2011-07-20 - 17:18 UnknownUser
png ljets_pt_m_3j.png r2 r1 manage 17.5 K 2011-07-19 - 20:32 UnknownUser
pdf mjets_btagmultiplicity_j_met.pdf r2 r1 manage 18.1 K 2011-07-19 - 21:04 UnknownUser
png mjets_btagmultiplicity_j_met.png r2 r1 manage 12.7 K 2011-07-19 - 21:03 UnknownUser
pdf mjets_eta_t_1t.pdf r4 r3 r2 r1 manage 22.1 K 2011-07-20 - 17:06 UnknownUser
png mjets_eta_t_1t.png r4 r3 r2 r1 manage 13.9 K 2011-07-20 - 17:05 UnknownUser
pdf mjets_multiplicity_j_3j.pdf r1 manage 20.2 K 2011-07-18 - 12:23 UnknownUser
png mjets_multiplicity_j_3j.png r1 manage 14.5 K 2011-07-18 - 12:23 UnknownUser
pdf mjets_pt_j_3j.pdf r1 manage 24.3 K 2011-07-18 - 12:55 UnknownUser
png mjets_pt_j_3j.png r1 manage 16.7 K 2011-07-18 - 12:46 UnknownUser
pdf mjets_pt_met_3j.pdf r3 r2 r1 manage 27.1 K 2011-07-20 - 21:14 UnknownUser
png mjets_pt_met_3j.png r3 r2 r1 manage 19.7 K 2011-07-20 - 21:30 UnknownUser
pdf mjets_pt_t_1t.pdf r1 manage 27.2 K 2011-07-19 - 20:18 UnknownUser
png mjets_pt_t_1t.png r2 r1 manage 18.1 K 2011-07-19 - 20:17 UnknownUser
pdf mjets_wjets.pdf r2 r1 manage 23.7 K 2011-07-19 - 21:36 ArunaNayak
png mjets_wjets.png r2 r1 manage 16.5 K 2011-07-19 - 21:35 ArunaNayak
pdf mutau_mtop_0.pdf r2 r1 manage 29.9 K 2011-07-18 - 14:34 UnknownUser
png mutau_mtop_0.png r1 manage 23.7 K 2011-07-18 - 14:36 UnknownUser
pdf mutau_mtop_modified.pdf r1 manage 32.8 K 2011-07-18 - 14:47 UnknownUser
png mutau_mtop_modified.png r1 manage 25.2 K 2011-07-18 - 14:48 UnknownUser
pdf pt_fakerate_hps0_dijet.pdf r1 manage 22.0 K 2011-07-18 - 14:45 UnknownUser
png pt_fakerate_hps0_dijet.png r1 manage 16.7 K 2011-07-18 - 14:44 UnknownUser
pdf pt_fakerate_hps0_wjet.pdf r1 manage 21.7 K 2011-07-18 - 13:11 UnknownUser
png pt_fakerate_hps0_wjet.png r1 manage 16.7 K 2011-07-18 - 13:12 UnknownUser
png table1.png r3 r2 r1 manage 53.5 K 2011-07-25 - 12:48 MicheleGallinaro
png table2.png r1 manage 47.1 K 2011-07-21 - 13:11 UnknownUser
png table2_b.png r1 manage 47.1 K 2011-07-21 - 13:14 UnknownUser
png xsec.png r1 manage 3.4 K 2011-07-18 - 15:54 UnknownUser
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Topic revision: r11 - 2011-10-10 - FrankPeterSchilling

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