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

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 t^~₁→ t(∗)χ^~0₁ and t^~₁→bχ^~±₁→bW(∗)χ~01, where χ₁(χ₁) 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 tχ^~0₁, top-squark masses in the range 450–1000 GeV are excluded for χ^~0₁ masses below 160 GeV. In the case where m^~_t1∼m_t+m_χ^~0₁, top-squark masses in the range 235–590 GeV are excluded.