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

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