Status of the Higgs singlet extension of the standard model after LHC run 1
Tania Robens (Institut für Kern- und Teilchenphysik, TU Dresden, Zellescher Weg 19, 01069, Dresden, Germany); Tim Stefaniak (Department of Physics, Santa Cruz Institute for Particle Physics, University of California, 95064, Santa Cruz, CA, USA)
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 from 1GeV to 1TeV accessible at past and current collider experiments. We separately discuss three scenarios, namely, the case where the second Higgs boson is lighter than, approximately equal to, or heavier than the discovered Higgs state at around 125GeV . We investigate the impact of constraints from perturbative unitarity, electroweak precision data with a special focus on higher-order contributions to the W boson mass, perturbativity of the couplings as well as vacuum stability. The latter two are tested up to a scale of ∼ 4×1010GeV using renormalization group equations. Direct collider constraints from Higgs signal rate measurements at the LHC and 95% confidence level 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.
