UC Santa Barbara

Results are reported from a search for supersymmetric particles in proton-proton colli- sions in the final state with a single, high transverse momentum lepton; multiple jets, including at least one b-tagged jet; and large missing transverse momentum. The search uses a 136 fb−1 sample of proton-proton collisions at √s = 13 TeV accumulated by the CMS experiment in 2016, 2017, and 2018. The search focuses on processes leading to high jet multiplicities, such as gluino pair production with g ̃ → t ̄tχ ̃01. The quantity MJ, defined as the sum of the masses of the large-radius jets in the event, is used in conjunction with other kinematic variables to provide discrimination between signal and background and as a key part of the background estimation method. The observed event yields in the signal regions in data are consistent with those expected for standard model backgrounds, estimated from control regions in data. Exclusion limits are obtained for a simplified model corresponding to gluino pair production with three-body decays into top quarks and neutralinos. Gluinos with a mass below about 2150 GeV are excluded at a 95% confidence level for scenarios with m(χ ̃01) < 700GeV, and the highest excluded neutralino mass is about 1250 GeV.