Measurements of the cross sections for top quark pairs produced in association with a W or Z boson are presented, using 8 TeV pp collision data corresponding to an integrated luminosity of 19.5 fb-1, collected by the CMS experiment at the LHC. Final states are selected in which the associated W boson decays to a charged lepton and a neutrino or the Z boson decays to two charged leptons. Signal events are identified by matching reconstructed objects in the detector to specific final state particles from ttÌW or ttÌZ decays. The ttÌW cross section is measured to be (Formula Presented) fb with a significance of 4.8 standard deviations from the background-only hypothesis. The ttÌZ cross section is measured to be (Formula Presented) fb with a significance of 6.4 standard deviations from the background-only hypothesis. These measurements are used to set bounds on five anomalous dimension-six operators that would affect the ttÌW and ttÌZ cross sections.
Observation of top quark pairs produced in association with a vector boson in pp collisions at âs = 8 TeV
CAPPELLO, GIGI;COSTA, Salvatore;GIORDANO, FERDINANDO;POTENZA, Renato Carlo;TRICOMI, Alessia Rita;TUVE', Cristina Natalina;
2016-01-01
Abstract
Measurements of the cross sections for top quark pairs produced in association with a W or Z boson are presented, using 8 TeV pp collision data corresponding to an integrated luminosity of 19.5 fb-1, collected by the CMS experiment at the LHC. Final states are selected in which the associated W boson decays to a charged lepton and a neutrino or the Z boson decays to two charged leptons. Signal events are identified by matching reconstructed objects in the detector to specific final state particles from ttÌW or ttÌZ decays. The ttÌW cross section is measured to be (Formula Presented) fb with a significance of 4.8 standard deviations from the background-only hypothesis. The ttÌZ cross section is measured to be (Formula Presented) fb with a significance of 6.4 standard deviations from the background-only hypothesis. These measurements are used to set bounds on five anomalous dimension-six operators that would affect the ttÌW and ttÌZ cross sections.File | Dimensione | Formato | |
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Observation of top quark pairs produced.pdf
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