Publication

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

Bibliographic Details
Summary:	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 = 13 TeV 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, t¯t and Z + jets production. A neural network is used to improve the background rejection and extract the signal. The resulting signiﬁcance is 4.2σ in the data and the expected signiﬁcance is 5.4σ . The measured cross-section for tZq production is 600±170 (stat.)±140 (syst.)fb.
Main Authors:	Onofre, A.
Other Authors:	Castro, Nuno Filipe; ATLAS Collaboration
Subject:	Ciências Naturais::Ciências Físicas
Year:	2018
Country:	Portugal
Document type:	article
Access type:	open access
Associated institution:	Universidade do Minho
Language:	English
Origin:	RepositóriUM - Universidade do Minho

Description
Summary:	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 = 13 TeV 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, t¯t and Z + jets production. A neural network is used to improve the background rejection and extract the signal. The resulting signiﬁcance is 4.2σ in the data and the expected signiﬁcance is 5.4σ . The measured cross-section for tZq production is 600±170 (stat.)±140 (syst.)fb.