Search for supersymmetry in events with b-tagged jets and missing transverse momentum in pp collisions at √s=13 TeV with the ATLAS detector

A search for the supersymmetric partners of the Standard Model bottom and top quarks is presented. The search uses 36.1 fb⁻¹ of pp collision data at √s=13 TeV collected by the ATLAS experiment at the Large Hadron Collider. Direct production of pairs of bottom and top squarks (b̄₁ and t̄₁) is searched for in final states with b-tagged jets and missing transverse momentum. Distinctive selections are defined with either no charged leptons (electrons or muons) in the final state, or one charged lepton. The zero-lepton selection targets models in which the b̄₁ is the lightest squark and decays via b̄₁→bχ̄₁⁰, where χ̄₁⁰ is the lightest neutralino. The one-lepton final state targets models where bottom or top squarks are produced and can decay into multiple channels, b̄₁→bχ̄₁⁰ and b̄₁→tχ̄₁^±, or t̄₁→tχ̄₁⁰ and t̄₁→bχ̄₁^±, where χ̄₁^± is the lightest chargino and the mass difference m_χ̄1^±−m_χ̄1⁰ is set to 1 GeV. No excess above the expected Standard Model background is observed. Exclusion limits at 95% confidence level on the mass of third-generation squarks are derived in various supersymmetry-inspired simplified models.