Aaboud, M.Aad, G.Abbott, B.Abdinov, O.Abeloos, B.Abidi, S. H.AbouZeid, O. S.Izen, Joseph M.Meirose, BernhardReeves, KendallATLAS Collaboration2019-08-302019-08-302018-07-091434-6044https://hdl.handle.net/10735.1/6802A search for new heavy particles that decay into top-quark pairs is performed using data collected from proton–proton collisions at a centre-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. The integrated luminosity of the data sample is 36.1 fb⁻¹. Events consistent with top-quark pair production are selected by requiring a single isolated charged lepton, missing transverse momentum and jet activity compatible with a hadronic top-quark decay. Jets identified as likely to contain b-hadrons are required to reduce the background from other Standard Model processes. The invariant mass spectrum of the candidate top-quark pairs is examined for local excesses above the background expectation. No significant deviations from the Standard Model predictions are found. Exclusion limits are set on the production cross-section times branching ratio for hypothetical Z′ bosons, Kaluza–Kein gluons and Kaluza–Klein gravitons that decay into top-quark pairs.enCC BY 4.0 (Attribution)©2018 CERN, for the ATLAS Collaborationhttp://creativecommons.org/licenses/by/4.0/QuarksProton-proton interactionsLarge Hadron Collider (France and Switzerland)Hadrons—DecayTransverse momentumJets (Nuclear physics)Standard model (Nuclear physics)Z bosonsKaluza-Klein theoriesarticleAaboud, M., G. Aad, B. Abbott, O. Abdinov, et al. 2018. "Search for heavy particles decaying into top-quark pairs using lepton-plus-jets events in proton–proton collisions at √s=13 TeV with the ATLAS detector." European Physical Journal C 78(7): art. 565, doi:10.1140/epjc/s10052-018-5995-678