Proton-proton collisions at the Large Hadron Collider at sqrt(s) = 7 and 8 TeV

are studied using the Compact Muon Solenoid (CMS) detector. The measurement and improvements to the arrival time of particles to the muon system of CMS are detailed. The timing is used to associate the particle with the correct proton-proton crossing and to classify the particle. Additionally, four analyses are presented that use timing and ionization energy loss to search for the production of long-lived charged particles predicted in many theories of new physics. The searches are sensitive to a variety of signatures, including the possibility that the particles will only be detectable during part of their passage through the CMS detector. Limits are placed on the production of long-lived gluinos, stops, staus, and multiply-charged particles. The limits are the most stringent in the world to date.

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.

This thesis first presents a detailed study of the Compact Muon Solenoid (CMS) Cathode Strip Chamber track stubs used to build muon tracks in the first layer of filtering, done in hardware, of the data. We study the spatial and angular resolutions of the track stubs with respect to the reconstructed hits using the full granularity data. We then move to a general description of a new technology, Gas Electron Multipliers (GEM), which is to be used in a near-future upgrade to the system. The characterization and calibration of the front-end electronics of the GEMs is discussed in detail. It is demonstrated that the noise of the electronics is sufficiently low to allow high efficiency operation of the technology with the first prototype GEM detector for the new subsystem. We then discuss the phenomenology of sphaleron-induced transition in proton-proton collisions. A new Monte Carlo generator is built to study this phenomenology in detail. We then perform a search analysis of the $35.9~\text{fb}^{-1}$ of data collected by the CMS detector in 2016. We set the first experimental upper limit on sphaleron production in proton-proton collisions.