Seminarium Kosmologia i Fizyka Cząstek

We discuss the current status of theoretical and experimental constraints on the real Higgs singlet extension of the Standard Model. For the second neutral (non-standard) Higgs boson we consider the full mass range up to 1 TeV which is accessible to past and present collider experiments. We investigate the impact of constraints from perturbative unitarity, higher order contributions to the W boson mass, perturbativity of the couplings as well as vacuum stability. Direct collider constraints from Higgs signal rate measurements at the LHC and exclusion limits from Higgs searches at LEP, Tevatron and LHC are included via the public codes HiggsSignals and HiggsBounds, respectively. We identify the strongest constraints in the different regions of parameter space. We comment on the collider phenomenology of the remaining viable parameter space and the prospects for a future discovery or exclusion at the LHC.