Performance and Calibrations of the Compact Muon Solenoid Muon System and a Search for Sphalerons at the Large Hadron Collider

This thesis 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 fb1of data collected by the CMS detector in 2016. We set the first experimental upper limit on sphaleron production in proton-proton collisions.