Doubly-charged scalar bosons from the doublet

Understand

We consider the extended Higgs models, in which one of the isospin doublet scalar fields carries the hypercharge Y=3/2.

• Such a doublet field $\Phi_{3/2}$ is composed of a doubly charged scalar boson as well as a singly charged one.
• We first discuss a simple model with $\Phi_{3/2}$ (Model I), and study its collider phenomenology at the LHC.
• We then consider a new model for radiatively generating neutrino masses with a dark matter candidate (Model II), in which $\Phi_{3/2}$ and an extra Y=1/2 doublet as well as vector-like singlet fermions carry the odd quantum number for an unbroken discrete $Z_2$ symmetry.