Measurement of electroweak processes in muon decay channels, in pp collisions at √s=7 TeV, in the CMS experiment at LHC

Abstract

This thesis covers different aspects of the Compact Muon Solenoid (CMS) operation and data analysis, always with muons as the common factor. The calibration and characterization of the drift tube chambers (DTs), one of CMS muon detectors, carried out in the pre-collision era, is presented in this thesis. To complete the calibration of the muon detection and measurement the calibration of muon momentum using electroweak data is shown. In particular, the clean sample that Z bosons coming from collisions represent is used to study the momentum scale and resolution of the CMS muon spectrometer. Finally, electroweak precision measurements are shown. The inclusive electroweak boson production cross section is the first electroweak measurement published by CMS. In this thesis, the inclusive W boson production cross section in the muonic channel with the whole 2010 data is measured. As a further step in the study of the W production, this time accompanied by jets, the analysis of the exclusive final state W+quark jets is both challenging and interesting from the physical point of view. The separation of W+quark from other W+quark jets is successfully achieved using c-tagging techniques what are new in CMS and useful for any other c jet studies. This analysis can constraint the quark strange content in the proton. Prospects to improve the measurement with 2011 data, as well as important distributions with 2 fb−1 are also reviewed in the last part of the thesis.