Search for supersymmetry in events with b-tagged jets and missing transverse momentum in pp collisions at √s̅=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 (b¯₁ and t¯₁) 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 b¯₁ is the lightest squark and decays via b¯₁→b_χ¯⁰₁, where χ¯⁰₁ is the lightest neutralino. The one-lepton final state targets models where bottom or top squarks are produced and can decay into multiple channels, b¯₁→b_χ¯⁰₁ and b¯₁→t_χ¯±, or t¯₁→t_χ¯⁰₁ and t¯₁→b_χ¯^±₁, where χ¯^±₁ is the lightest chargino and the mass difference m_χ¯±₁−m_χ¯0₁ 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.