Search For Long Lived Particles That Decay To Muon Pairs At 13 Tev And An Algorithm To Improve Resolution In The Muon System Of The Compact Muon Solenoid

This thesis presents a search for new long-lived particles decaying to two muons in the Compact Muon Solenoid (CMS) detector using proton-proton collision data taken at √s = 13 TeV corresponding to 96.6 fb−1 of integrated luminosity during the Run 2 of the Large Hadron Collider (LHC). The search spans the full extent of the CMS detector and probes vertices displaced from the interaction point ranging from less than a millimeter to multiple meters. No evidence for beyond the standard model physics is observed. Results are interpreted in the context of both scalar and vector models for the long-lived particle. We also present a detailed description of a novel algorithm for the endcap muon system of CMS which improves muon resolution of the Level-1 Trigger to be implemented for the upcoming Run 3 data taking period.