Search for new resonances in p-p collisions using fully leptonic W+W− decays with the CMS detector

This thesis presents a search for a possible heavy Higgs boson, X, decaying into a pair of W bosons, in the mass range from 200 GeV to 3 TeV. The analysis is based on proton-proton collisions recorded by the CMS experiment at the CERN LHC in 2016, corresponding to an integrated luminosity of 35.9 fb −1 at sqrt{s}=13 TeV. The W boson pair decays are reconstructed in the 2l2ν and lνqq̄ final states. Both gluon-gluon fusion and electroweak production of the scalar resonance are considered. Dedicated event categorizations, based on the kinematic properties of the final states, are employed for an optimal signal-to-background separation. Combined upper limits at the 95% confidence level on the product of the cross section and branching fraction excludes a heavy Higgs boson with Standard Model-like couplings and decays in the range of mass investigated.