Saving the Higgs Portal for Singlet Scalar Dark Matter

Abstract

The Higgs-portal model with a singlet scalar Dark Matter particle is one of the simplest extensions to the Standard Model that can reproduce the relic density. Unfortunately this model is strongly constrained by direct and indirect DM detection, as well as by collider physics. Most of the parameter space is already ruled-out and the rest will be explored in the next future. We show that a simple extension of the DM sector with a second scalar singlet enables a substantial opening of the allowed window in the parameter space.