The Higgs Portal to Cosmology

Abstract

The discovery of the Higgs boson has opened a new avenue for exploring physics beyond the Standard Model. In this review, we discuss cosmological aspects of the simplest Higgs couplings to the hidden sector, known as the Higgs portal. We focus on implications of such couplings for inflation, vacuum stability and dark matter, with the latter including both the traditional weakly interacting massive particles as well as feebly interacting scalars. The cosmological impact of the Higgs portal can be important even for tiny values of the couplings.