Inflation and dark matter in two Higgs doublet models

TL;DR

This paper explores Higgs inflation in two Higgs doublet models, examining how symmetry and inflationary constraints influence dark matter candidates and Higgs sector parameters.

Contribution

It analyzes inflationary dynamics in two Higgs doublet models with global symmetries, linking inflation constraints to dark matter properties and Higgs sector stability.

Findings

Inflation driven by neutral Higgs modes with potential for large non-Gaussianity.

Dark matter candidate can be light or heavy depending on inflation scenario.

Parameter space constrained by inflation, perturbativity, and stability conditions.

Abstract

We consider the Higgs inflation in the extension of the Standard Model with two Higgs doublets coupled to gravity non-minimally. In the presence of an approximate global U(1) symmetry in the Higgs sector, both radial and angular modes of neutral Higgs bosons drive inflation where large non-Gaussianity is possible from appropriate initial conditions on the angular mode. We also discuss the case with single-field inflation for which the U(1) symmetry is broken to a Z_2 subgroup. We show that inflationary constraints, perturbativity and stability conditions restrict the parameter space of the Higgs quartic couplings at low energy in both multi- and single-field cases. Focusing on the inert doublet models where Z_2 symmetry remains unbroken at low energy, we show that the extra neutral Higgs boson can be a dark matter candidate consistent with the inflationary constraints. The doublet dark matter is always heavy in multi-field inflation while it can be light due to the suppression of the co-annihilation in single-field inflation. The implication of the extra quartic couplings on the vacuum stability bound is also discussed in the light of the recent LHC limits on the Higgs mass.