Observation of a New Particle in the Search for the Standard Model Higgs Boson at the CMS Detector

The discovery of the Standard Model (SM) Higgs boson is one of theprimary physics objectives of the Large Hadron Collider at CERN. Thisthesis describes a search carried out for the SM Higgs boson on data collected during the 2011 and 2012 proton-proton (pp) collision runs withthe CMS detector corresponding to integrated luminosities of 5.1f b−1and 5.3f b−1 respectively. A detailed description of the search for theSM Higgs boson decaying to two photons from the full dataset collectedat CMS during the 2011 pp collision run is provided. In particular, thedevelopment of signal and background modelling techniques used forstatistical interpretations of the data are highlighted. Results of thesearch using these techniques from the 2011 dataset are presented. Inaddition, an update to the analysis including data taken during 2012is described and the results from the combined 2011 and 2012 analysesgiven. Results from the combination of several Higgs decay channels atCMS are reported, including those presented in the International Conference on High Energy Physics in July 2012 at which the announcement ofdiscovery was made. Ongoing studies to ascertain the properties of thenew particle are discussed and preliminary results from the combined 7and 8 TeV datasets (corresponding to 5.1f b−1 and 12.2f b−1 respectively)are presented.