Search for four-top-quark production in the single-lepton and opposite-sign dilepton final states in pp collisions at $sqrt{s}=13TeV$ with the ATLAS detector

A search for the production of $t\bar{t}t\bar{t}$ using proton-proton collisions data at center of mass energy $sqrt{s} = 13TeV$ with an integrated luminosity of 36 $fb^{-1}$ recorded by the ATLAS experiment is presented. The considered final stats are events with multiple jets, b-jets, and either one lepton or two opposite sign leptons with high-transverse momentum. The result is combined with the previous study on same-sign dilepton and multileptons searches carried out by ATLAS. No significant excess above the Standard Model expectation is observed.