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 t (t) over barW or t (t) over barZ decays. The t (t) over barW cross section is measured to be 382(-102)(+117) fb with a significance of 4.8 standard deviations from the background-only hypothesis. The t (t) over barZ cross section is measured to be 242(-55)(+65) 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 t (t) over barW and t (t) over barZ cross sections.
Observation of top quark pairs produced in association with a vector boson in pp collisions at root s=8 TeV
ZOTTO, PIERLUIGI;BENATO, LISA;BISELLO, DARIO;BOLETTI, ALESSIO;CARLIN, ROBERTO;CHECCHIA, PAOLO;DALL'OSSO, MARTINO;GASPARINI, FABRIZIO;GASPARINI, UGO;GOZZELINO, ANDREA;LACAPRARA, STEFANO;MARGONI, MARTINO;PAZZINI, JACOPO;POZZOBON, NICOLA;RONCHESE, PAOLO;SIMONETTO, FRANCO;TOSI, MIA;VANINI, SARA;ZANETTI, MARCO;ZUCCHETTA, ALBERTO;ZUMERLE, GIANNI;Triossi, A.;Veres, G. I.;Gaz, A.;ROSSIN, ROBERTO;
2016
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 t (t) over barW or t (t) over barZ decays. The t (t) over barW cross section is measured to be 382(-102)(+117) fb with a significance of 4.8 standard deviations from the background-only hypothesis. The t (t) over barZ cross section is measured to be 242(-55)(+65) 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 t (t) over barW and t (t) over barZ cross sections.Pubblicazioni consigliate
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