A search is presented for four-top-quark production using an integrated luminosity of 139 fb-1 of proton–proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the LHC. Events are selected if they contain a same-sign lepton pair or at least three leptons (electrons or muons). Jet multiplicity, jet flavour and event kinematics are used to separate signal from the background through a multivariate discriminant, and dedicated control regions are used to constrain the dominant backgrounds. The four-top-quark production cross section is measured to be 24-6+7 fb. This corresponds to an observed (expected) significance with respect to the background-only hypothesis of 4.3 (2.4) standard deviations and provides evidence for this process.

Evidence for tt¯ tt¯ production in the multilepton final state in proton–proton collisions at sqrt(s) = 13 TeV with the ATLAS detector

G Chiodini;E Gorini;F Gravili;L Longo;M Reale;E Schioppa;S Spagnolo;A Ventura;
2020-01-01

Abstract

A search is presented for four-top-quark production using an integrated luminosity of 139 fb-1 of proton–proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the LHC. Events are selected if they contain a same-sign lepton pair or at least three leptons (electrons or muons). Jet multiplicity, jet flavour and event kinematics are used to separate signal from the background through a multivariate discriminant, and dedicated control regions are used to constrain the dominant backgrounds. The four-top-quark production cross section is measured to be 24-6+7 fb. This corresponds to an observed (expected) significance with respect to the background-only hypothesis of 4.3 (2.4) standard deviations and provides evidence for this process.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11587/455155
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