Search for pair-production of gluinos decaying via stop and sbottom in events with $b$-jets and large missing transverse momentum in $\sqrt{s}=13$ TeV $pp$ collisions with the ATLAS detector

A search for pair-production of gluinos decaying via third generation squarks to the lightest neutralino ($\displaystyle\tilde\chi^0_1$) is reported. It uses an LHC proton-proton dataset at a centre-of-mass energy $\sqrt{s} = 13$ TeV with an integrated luminosity of 3.3 fb$^{-1}$ collected with the ATLAS detector in 2015. The signal is searched for in events containing several energetic jets, of which at least three must be identified as $b$-jets, large missing transverse momentum and potentially isolated charged electrons or muons. Massive large-radius jets are also used to identify highly boosted top quarks. The data are found to be in good agreement with the predicted background yield. For $\displaystyle\tilde\chi^0_1$ masses below approximately 700 GeV, gluino masses of less than 1780 GeV and 1675 GeV are excluded at the 95% CL in simplified models of the pair-production of gluinos decaying via sbottom and stop, respectively.