Search for same-charge top-quark pair production in pp collisions at SQUARE ROOTs = 13 TeV with the ATLAS detector

Abstract

A search for the production of top-quark pairs with the same electric charge (tt or-t-t) is presented. The analysis uses proton-proton collision data at SQUARE ROOTs = 13TeV, recorded bythe ATLAS detector at the Large Hadron Collider, corresponding to an integrated luminosityof 140 fb-1. Events with two same-charge leptons and at least two b-tagged jets are selected.Neural networks are employed to define two selections sensitive to additional couplings beyondthe Standard Model that would enhance the production rate of same-sign top-quark pairs. Nosignificant signal is observed, leading to an upper limit on the total production cross-sectionof same-sign top-quark pairs of 1.6 fb at 95% confidence level. Corresponding limits on thethree Wilson coefficients associated with the O(1)tu , O(1)Qu, and O(8)Qu operators in the StandardModel Effective Field Theory framework are derived.