Search for gluino-mediated stop pair production in events with b-jets and large missing transverse momentum

A search for supersymmetry involving the pair production of gluions decaying via stop quarks into the lightest neutralino is reported. The search uses LHC proton-proton collision data at the center-of-mass energy sqrt(s)=13 TeV with an integrated luminosity of 79.8 inverse fb collected with the ATLAS detector in 2015-2017. The search is performed in events containing large missing transverse momentum and several energetic jets, at least three of which must be identified as originating from b-quarks. The analysis considers two final states, one of which is required to have at least one lepton, while the second search region imposes a veto on leptons. Expected exclusion limit for gluino and neutralino masses is evaluated using simplified signal models.