Search for a scalar partner of the top quark in the jets plus missing transverse momentum final state at √s = 13 TeV with the ATLAS detector

Abstract

A search for pair production of a scalar partner of the top quark in events with four or more jets plus missing transverse momentum is presented. An analysis of 36.1 fb^-1 of √s = 13 TeV proton-proton collisions collected using the ATLAS detector at the LHC yields no significant excess over the expected Standard Model background. To interpret the results a simplified supersymmetric model is used where the top squark is assumed to decay via ~t₁ → t(*) ~X⁰₁ and ~t₁ → b~X^±₁ → bW(*) ~X⁰₁, where ~X⁰₁ (~X^±₁) denotes the lightest neutralino (chargino). Exclusion limits are placed in terms of the top-squark and neutralino masses. Assuming a branching ratio of 100% to t ~X⁰₁, top-squark masses in the range 450-1000 GeV are excluded for ~X⁰₁ masses below 160 GeV. In the case where m_~t₁ ~ m_t +m_~X⁰₁ , top-squark masses in the range 235-590 GeV are excluded.