Observation of top quark pairs produced in association with a vector boson in pp collisions at √ s =8 TeV

Khachatryan, V. and Sirunyan, A.M. and Tumasyan, A. and Adam, W. and Asilar, E. and Filipovic, Nicolas and Bencze, György and Hajdú, Csaba and Hidas, Pál and Horváth, Dezső and Siklér, Ferenc and Veszprémi, Viktor and Vesztergombi, György and Zsigmond, Anna Júlia and Karancsi, János and Molnár, József and Bartók, Márton and Makovec, Alajos and Trócsányi, Zoltán and Ujvári, Balázs and Veres, Gábor (2016) Observation of top quark pairs produced in association with a vector boson in pp collisions at √ s =8 TeV. JOURNAL OF HIGH ENERGY PHYSICS (1). ISSN 1126-6708

Preview

Text 1510.01131.pdf Available under License Creative Commons Attribution. Download (1MB) | Preview

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 inverse-femtobarns, 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 ttW or ttZ decays. The ttW cross section is measured to be 382 +117 -102 fb with a significance of 4.8 standard deviations from the background-only hypothesis. The ttZ cross section is measured to be 242 +65 -55 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 ttW and ttZ cross sections.

Actions (login required)

Edit Item