Electroweak right-handed neutrinos and new signals at the LHC

Abstract

We explore in detail the Higgs phenomenology that results in a model where right-handed neutrinos have a mass scale of the order of the electroweak scale. In this model all scales arise from spontaneous symmetry breaking, and this is achieved with a Higgs sector that includes an extra Higgs singlet in addition to the standard model Higgs doublet. The scalar spectrum includes two neutral CP-even states ($h$ and $H$ with $m_{h} < m_{H}$)and a neutral CP-odd state ($\sigma$) that can be identified as a pseudo-Majoron. The parameter of the Higgs potential are constrained using a perturbativity criteria. Higgs BR and cross-sections are discussed, with special emphasis on the detection at the LHC.