UC Santa Barbara

This dissertation describes a search for supersymmetry in 35.9 fb^{-1} of proton-proton collisions with sqrt(s) = 13 TeV produced by the LHC and recorded by the CMS experiment. The search targets events having a final state with a single lepton, high jet multiplicity, at least one b-tagged jet, and missing transverse momentum. Standard model background yields are estimated using the sum of the masses of large-radius jets in each event. The observed yields are consistent with the estimated background yields. This consistency is interpreted in term of simplified models of supersymmetry in which gluinos are pair produced and each subsequently decay into a top quark, anti-top quark, and neutralino via an intermediate on- or off-shell stop squark. Assuming a 100% branching fraction for this decay chain, gluino masses up to approximately 1.9 TeV are excluded at a 95% confidence level for neutralino masses below 1 TeV. Similarly, neutralino masses up to approximately 1175 GeV are excluded when the gluino mass is 1.7 TeV.