UC Santa Barbara

The discovery of the Higgs boson casts new urgency to an old question: the Higgs mass hierarchy problem. Supersymmetry can provide an elegant and natural solution to the hierarchy problem, and would result in many new particles accessible at the TeV scale probed by the LHC.

This dissertation describes a search for a classic natural supersymmetry signature, gluino mediated top squark production. The search is performed in the single-lepton final state, relying on the large missing energy and high jet and b-flavor jet multiplicities to separate the gluino signal from the Standard Model backgrounds. The background measurement is centered around the variable MJ, the sum of masses of large radius jets. The search uses a sample of proton-proton collisions at center of mass energy 13 TeV recorded by the CMS detector, corresponding to an integrated luminosity of 35.9 /fb. The observed yields in the signal regions are consistent with the expected Standard Model backgrounds, and the results are interpreted in the context of simplified models of gluino pair production. Scenarios with gluino masses up to approximately 1.9 TeV are excluded at 95% confidence level for neutralino masses less than 1 TeV. This negative result joins a substantial body of evidence disfavoring supersymmetry realized near the electroweak scale.