Fermiophobia in a Higgs triplet model

Abstract

A fermiophobic Higgs boson can arise in models with an extended Higgs sector, such as models with scalars in an isospin triplet representation. In a specific model with a scalar triplet and spontaneous violation of lepton number induced by a scalar singlet field, we show that fermiophobia is not a fine-tuned situation, unlike in two higgs doublet models. We study distinctive signals of fermiophobia which can be probed at the LHC. For the case of a small Higgs mass, a characteristic signal would be a moderate $B(H\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma})$ accompanied by a large $B(H\ensuremath{\rightarrow}JJ)$ (where $J$ is a Majoron), the latter being an invisible decay. For the case of a large Higgs mass there is the possibility of dominant $H\ensuremath{\rightarrow}ZZ$, $WW$ and suppressed $H\ensuremath{\rightarrow}JJ$ decay modes. In this situation, $B(H\ensuremath{\rightarrow}ZZ)$ is larger than $B(H\ensuremath{\rightarrow}WW)$, which differs from the SM prediction.