UC Santa Barbara

Results are presented for a search for top squark pair production using a sample of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the CMS experiment at the LHC during 2016, 2017 and 2018, corresponding to an integrated luminosity of 137.2 fb^{-1}. The search is carried out using events with a single isolated electron or muon, multiple jets and large transverse momentum imbalance and is tuned to have high sensitivities for a variety of top squark pair production processes, as described by simplified models of supersymmetry. Novel techniques have been applied to boost the signal sensitivity and data-driven methods have been applied to estimate the main backgrounds. The observed data are found to be consistent with expectations from Standard Model processes, and exclusions are set in the context of simplified top squark pair production models in terms of the masses of the top squark and the lightest supersymmetric particle, assumed to be the neutralino. Depending on the model, top squark masses up to 1.2 TeV are excluded for models with a massless neutralino, while neutralino of masses up to 600 GeV are excluded for models with top squark masses of 1 TeV, at the 95% confidence level.