The production of a top quark in association with a Z boson is investigated. The proton–proton collision data collected by the ATLAS experiment at the LHC in 2015 and 2016 at a centre-of-mass energy of s=13TeV are used, corresponding to an integrated luminosity of 36.1fb−1 . Events containing three identified leptons (electrons and/or muons) and two jets, one of which is identified as a b -quark jet are selected. The major backgrounds are diboson, tt¯ and Z+jets production. A neural network is used to improve the background rejection and extract the signal. The resulting significance is 4.2 σ in the data and the expected significance is 5.4 σ . The measured cross-section for tZq production is 600±170(stat.)±140(syst.)fb .
Measurement of the production cross-section of a single top quark in association with a Z boson in proton–proton collisions at 13 TeV with the ATLAS detector
Dondero P.;Farina E. M.;Fraternali M.;Introzzi G.;Livan M.;Negri A.;Rebuzzi D. M.;Rimoldi A.;Sottocornola S.;
2018-01-01
Abstract
The production of a top quark in association with a Z boson is investigated. The proton–proton collision data collected by the ATLAS experiment at the LHC in 2015 and 2016 at a centre-of-mass energy of s=13TeV are used, corresponding to an integrated luminosity of 36.1fb−1 . Events containing three identified leptons (electrons and/or muons) and two jets, one of which is identified as a b -quark jet are selected. The major backgrounds are diboson, tt¯ and Z+jets production. A neural network is used to improve the background rejection and extract the signal. The resulting significance is 4.2 σ in the data and the expected significance is 5.4 σ . The measured cross-section for tZq production is 600±170(stat.)±140(syst.)fb .I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.