Combined search for four-top quarks production in proton-proton collisions at $\sqrt {s}$ = 13 TeV with the ATLAS detector

The combination of two analyses searching for the production of four-top quarks ($t$$\bar{t}$ $t$$\bar{t}$) using proton-proton collision data at a center-of-mass energy $\sqrt{s}$ = 13 TeV with an integrated luminosity of 36 fb$^{−1}$ recorded by the ATLAS experiment is presented. The considered final states are events with multiple jets, b-jets, and either: a) one lepton or two leptons with an opposite electric charge, or b) two leptons with the same electric charge or three leptons. Constraints are set on production $t$$\bar{t}$ $t$$\bar{t}$ cross-section and on an effective field theory inducing four fermions contact interactions.