Search for the Standard Model Higgs Boson Decaying to Two W Bosons at CMS

In this thesis, we search for the production of the Standard Model Higgs boson at the Large Hadron Collider, through its decay mode to two W bosons, which each in turn decay into a charged lepton and a neutrino. The Higgs boson is the only elementary particle predicted by the Standard Model of particle physics which has not yet been experimentally observed. The question of its existence has been the subject of a wide body of experimental and theoretical work for the past half-century. Using 4.9 fb^−1 of integrated luminosity, this search is expected, on average, to exclude the Standard Model predicted Higgs boson production cross section for masses between 126 GeV/c^2 and 260 GeV/c^2 under the background-only hypothesis. We observe no statistically significant excesses in the data, and we exclude the Standard Model Higgs boson production for masses between 129 GeV/c^2 and 260 GeV/c^2 . This result represents a significant reduction of the mass region in which the Standard Model Higgs boson is allowed to exist.