Resumen de Search for high mass Higgs bosons in the l?l?qq¯ final state in CMS
The work presented in this thesis is the analysis using CMS data of the search for Higgs bosons in the decay mode H to ZZ to LLQQ, where the Higgs boson (H) decays into two Z bosons which subsequently decay to a lepton pair (L) and a quark-antiquark pair (Q), respectively. The data sample used in this work consist on proton-proton collisions at centre-of-mass energies of 8 TeV provided by the LHC and collected by the Compact Muon Solenoid.
This analysis was originally designed to discover the Standard Model (SM) Higgs boson in the high mass region, up to 1 TeV. After the discovery of the SM Higgs boson with a mass of 125 GeV by the ATLAS and CMS Collaborations, this work contributed to establish the SM nature of the new boson by excluding additional Higgs bosons at 95% of confidence level with masses in the range between 285 and 777 GeV. The results the analysis are combined with other Higgs boson searches inside CMS, using the H to ZZ and H to WW decay modes, excluding the existence of a SM Higgs boson with masses from 145 GeV to 1 TeV.
At that point, the analysis was significantly improved and turned into a search for Beyond the Standard Model (BSM) Higgs bosons, probing a simple extension with an additional electroweak singlet field, mixed with the SM Higgs doublet field. Failing to unveil BSM Higgs boson signals with the limited number of events collected by CMS in LHC Run I, we have been able to exclude ample regions of the parameter space in this model, which can be easily interpreted as constraints on parameters of Two-Higgs doublet models.
Profiting from the advanced analysis techniques developed in this work, the analysis of larger data samples from Run II of the LHC will allow to search for heavy additional Higgs boson signals, probing different BSM extensions of the Standard Model.
