Aad, G.Abbott, B.Abbott, D.C.Abed Abud, A.Abeling, K.Abhayasinghe, D.K.Abidi, S.H.Abramowicz, H.Abreu, H.Abulaiti, Y.Abusleme Hoffman, A.C.Acharya, B.S.Achkar, B.Adam, L.Adam Bourdarios, C.Adamczyk, L.Adamek, L.Adelman, J.Adiguzel, A.Adorni, S.Adye, T.Affolder, A.A.Afik, Y.Agapopoulou, C.Agaras, M.N.Agarwala, J.Aggarwal, A.Agheorghiesei, C.Aguilar-Saavedra, J.A.Ahmad, A.Ahmadov, F.Ahmed, W.S.Ai, X.Aielli, G.Akatsuka, S.Akbiyik, M.Åkesson, T.P.A.Akimov, A.V.Al Khoury, K.Alberghi, G.L.Albert, J.Alconada Verzini, M.J.Alderweireldt, S.Aleksa, M.Aleksandrov, I.N.Alexa, C.Alexopoulos, T.Alfonsi, A.Alfonsi, F.Alhroob, M.Ali, B.Ali, S.Aliev, M.Alimonti, G.Allaire, C.Allbrooke, B.M.M.Allport, P.P.Aloisio, A.Alonso, F.Alpigiani, C.2025-03-182025-03-182021-11Journal of High Energy Physics, Volume 2021, Issue 11, November 2021, Article number 1181029-8479https://repositorio.unab.cl/handle/ria/63815Indexación: Scopus.A measurement of four-top-quark production using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS detector at the Large Hadron Collider corresponding to an integrated luminosity of 139 fb−1 is presented. Events are selected if they contain a single lepton (electron or muon) or an opposite-sign lepton pair, in association with multiple jets. The events are categorised according to the number of jets and how likely these are to contain b-hadrons. A multivariate technique is then used to discriminate between signal and background events. The measured four-top-quark production cross section is found to be 26−15+17 fb, with a corresponding observed (expected) significance of 1.9 (1.0) standard deviations over the background-only hypothesis. The result is combined with the previous measurement performed by the ATLAS Collaboration in the multilepton final state. The combined four-top-quark production cross section is measured to be 24−6+7 fb, with a corresponding observed (expected) signal significance of 4.7 (2.6) standard deviations over the background-only predictions. It is consistent within 2.0 standard deviations with the Standard Model expectation of 12.0 ± 2.4 fb. [Figure not available: see fulltext.]. © 2021, The Author(s).enHadron-Hadron scattering (experiments)Top physicsArtículoAttribution 4.0 International CC BY 4.0 Deed10.1007/JHEP11(2021)118