Normalized differential ttbar quark pair production cross sections in pp-collisions at sqrt{s} = 7 TeV are measured using a dataset recorded by the CMS experiment in 2011 corresponding to an integrated luminosity of 1.14 fb-1. The measurement is performed in the semileptonic decay channels (muon+jets and electron+jets) and the decay channels into two opposite-sign leptons (m+m-, e+e- and m+/- e-/+) in the final state. The cross section distributions are measured as a function of kinematic observables of the final state leptons and the top quarks, as reconstructed by algorithms fitting the ttbar event topologies. The measurement also includes the invariant mass distribution of ttbar quark pairs. The measurement shows good agreement with predictions from QCD models.
The document CMS-PAS-TOP-11-013 published on the CERN document server can be found here.
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Basic kinematic distributions after event selection for mu+jets channel: number of b-tagged jets before requiring any selection on this variable, illustrating that the main background from W+jets is efficiently suppressed by requiring b-tagging. The simulated events are corrected for trigger and lepton selection efficiencies. The hatched area represents the uncertainty coming from the inclusive ttbar cross section measurement and the luminosity. [Get pdf version] | |
Basic kinematic distributions after event selection for mu+jets: jet multiplicity after requiring b-tagging demonstrating that mainly ttbar events are selected. The simulated events are corrected for trigger and lepton selection efficiencies. After imposing the b-tag requirement, the events are scaled with a b-tagging efficiency in addition. The hatched area represents the uncertainty coming from the inclusive ttbar cross section measurement and the luminosity. [Get pdf version] | |
Basic kinematic distributions after event selection for e+jets channel: number of b-tagged jets before requiring any selection on this variable, illustrating that the main background from W+jets is efficiently suppressed by requiring b-tagging. The simulated events are corrected for trigger and lepton selection efficiencies. The hatched area represents the uncertainty coming from the inclusive ttbar cross section measurement and the luminosity. [Get pdf version] | |
Basic kinematic distributions after event selection for e+jets: jet multiplicity after requiring b-tagging demonstrating that mainly ttbar events are selected. The simulated events are corrected for trigger and lepton selection efficiencies. After imposing the b-tag requirement, the events are scaled with a b-tagging efficiency in addition. The hatched area represents the uncertainty coming from the inclusive ttbar cross section measurement and the luminosity. [Get pdf version] |
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Basic kinematic distributions after event selection for the dilepton channels: transverse momentum pT of the selected isolated leptons. The Drell--Yan background is rescaled to the data-driven estimated factor given in the legends. The hatched area represents the uncertainty coming from the inclusive ttbar cross section measurement and the luminosity. [Get pdf version] | |
Basic kinematic distributions after event selection for the dilepton channels: transverse momentum pT of the reconstructed jets. The Drell--Yan background is rescaled to the data-driven estimated factor given in the legends. The hatched area represents the uncertainty coming from the inclusive ttbar cross section measurement and the luminosity. [Get pdf version] | |
Basic kinematic distributions after event selection for the dilepton channels: multiplicity of the reconstructed jets after b-tagging. The Drell--Yan background is rescaled to the data-driven estimated factor given in the legends. The hatched area represents the uncertainty coming from the inclusive ttbar cross section measurement and the luminosity. [Get pdf version] | |
Basic kinematic distributions after event selection for the dilepton channels: multiplicity of b-tagged jets. The Drell--Yan background is rescaled to the data-driven estimated factor given in the legends. The hatched area represents the uncertainty coming from the inclusive ttbar cross section measurement and the luminosity. [Get pdf version] |
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Combined normalized differential cross sections in the lepton+jets channel: lepton pT. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] [Get pdf version in linear scale] | |
Combined normalized differential cross sections in the lepton+jets channel: lepton pseudo-rapidity. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] | |
Combined normalized differential cross sections in the lepton+jets channel: top/antitop pT. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] [Get pdf version in linear scale] | |
Combined normalized differential cross sections in the lepton+jets channel: top/antitop rapidity. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] | |
Combined normalized differential cross sections in the lepton+jets channel: pT of the ttbar system. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] [Get pdf version in linear scale] | |
Combined normalized differential cross sections in the lepton+jets channel: rapidity of the ttbar system. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] | |
Combined normalized differential cross sections in the lepton+jets channel: invariant mass of the ttbar system. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] |
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Combined normalized differential cross sections in the dilepton channel: leptons pT. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] [Get pdf version in linear scale] | |
Combined normalized differential cross sections in the dilepton channel: leptons pseudo-rapidity. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] | |
Combined normalized differential cross sections in the dilepton channel: pT of the lepton pair. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] [Get pdf version in linear scale] | |
Combined normalized differential cross sections in the dilepton channel: invariant mass of the lepton pair. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] | |
Combined normalized differential cross sections in the dilepton channel: top/antitop pT. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] [Get pdf version in linear scale] | |
Combined normalized differential cross sections in the dilepton channel: top/antitop rapidity. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] | |
Combined normalized differential cross sections in the dilepton channel: pT of the ttbar system. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] [Get pdf version in linear scale] | |
Combined normalized differential cross sections in the dilepton channel: rapidity of the ttbar system. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] | |
Combined normalized differential cross sections in the dilepton channel: invariant mass of the ttbar system. The inner error bars indicate the statistical uncertainty and the outer error bars the combined statistical and systematic uncertainty. The measurements are compared to predictions from MadGraph, POWHEG, and MC@NLO Monte Carlo generators. For the MadGraph comparison both a smooth curve and a binned histogram are shown. The latter indicates the bins of the cross section measurement. [Get pdf version] |