Search for cascade decays of charged sleptons and sneutrinos in final states with three leptons and missing transverse momentum in pp collisions at SQUARE ROOTs = 13 TeV with the ATLAS detector

Abstract

A search for cascade decays of charged sleptons and sneutrinos using final states characterized by threeleptons (electrons or muons) and missing transverse momentum is presented. The analysis is based on adataset with 140 fb-1 of proton-proton (pp) collisions at a center-of-mass energy offfiffiffisp1/4 13 TeV recordedby the ATLAS detector at the Large Hadron Collider. This paper focuses on a supersymmetric scenario thatis motivated by the muon anomalous magnetic moment observation, dark-mattter relic density abundance,and electroweak naturalness. A mass spectrum involving light Higgsinos and heavier sleptons with a binoat intermediate mass is targeted. No significant deviation from the Standard Model expectation is observed.This search enables us to place stringent constraints on this model, excluding at the 95% confidence levelcharged slepton and sneutrino masses up to 450 GeV when assuming a lightest neutralino mass of 100 GeVand mass-degenerate selectrons, smuons and sneutrinos.