ATLAS Collab.
Evidence for tttt production in the multilepton final state in proton-proton collisions at √s=13 TeV with the ATLAS detector
In total, 12 observables are selected. Among them, the pseudo-continuous b-tagging discriminant score summed over all the jets in the event is the best discriminating variable due to the four b-jets being produced mainly in signal events. The pseudo-continuous b-tagging discriminant score is an integer from 1 to 5 assigned to a jet, based on the operating point of the b-tagging algorithm it passes, with a value of five corresponding to the most b-like jet. The minimum distance ∆R between two leptons among all possible pairs is the second best discriminating variable since it provides good discrimination for events with at least three leptons. The other input variables are the leading lepton pT, ETmiss , the pT of the leading and second-leading jets, the pT of the sixth jet, the pT of the leading b-jet, the scalar sum of transverse momenta over all leptons and all jets excluding the leading pT jet, the sum of distances ∆R between two leptons for all possible pairs, the maximum distance ∆R between a b-jet and a lepton among all possible pairs, and the minimum distance ∆R between a jet and a b-jet among all possible pairs.