Search for four-top-quark production in the single-lepton and opposite-sign dilepton final states in proton-proton collisions at √s = 13 TeV with the ATLAS detector

Recent published results on a search for four-top-quark production, tttt, are presented, based on a dataset collected at √s = 13 TeV with the ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosity of 36.1 fb−1. The single-lepton and opposite-sign dilepton final states are analysed. The search exploits the high multiplicity of jets/b-tagged jets and the large total sum of jet transverse momenta, which characterise signal events and provide a good discrimination against the tt+jets dominant background, which is estimated through a data-driven method. No significant excess above the Standard Model expectation is observed.