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

Abstract

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→bχ¯¯¯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→bχ¯¯¯01 and b¯¯1→tχ¯¯¯±1, or t¯1→tχ¯¯¯01 and t¯1→bχ¯¯¯±1, where χ¯¯¯±1 is the lightest chargino and the mass difference mχ¯¯¯¯±1−mχ¯¯¯¯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.