Speaker
Description
We consider the extension of the SM with an inert scalar doublet,
three right-handed neutrinos, and singlet scalar fields, ϕ and S. In this model, neutrino
masses are zero in the limit of the unbroken Z4 discrete symmetry. We show that when the
singlet scalar field ϕ gets a VEV, the Z4 symmetry is broken to Z2, and neutrino masses
are generated at one-loops due to the mixings between the neutral components of the inert
scalar doublet and the singlet scalar field S. There is a dark matter candidate from the
lightest neutral scalar field, which is a mixture of the inert scalar doublet and the singlet
scalar field S, in general. The Z4 breaking mass terms are constrained by electroweak
precision data and direct detection (DD) bounds for dark matter, favoring small mixings
or almost degenerate masses for the DM scalars. As a result, we discuss the implications
of the results for small neutrino masses and DD-safe dark matter. Finally, we discuss on the possible collider signatures in our model.