Inflation and Dark Matter in the Inert Doublet Model

TL;DR

This paper explores a model where the inert doublet serves as both the inflaton and dark matter candidate, analyzing inflationary parameters and the reheating process leading to dark matter freeze-out.

Contribution

It introduces a non-minimally coupled inert doublet model where the same scalar drives inflation and accounts for dark matter, with detailed reheating and freeze-out analysis.

Findings

Inflationary parameters $n_s$, $r$, and $P_s$ are calculated.

Reheating involves decay into Higgs and gauge bosons, leading to relativistic fermions.

Dark matter with a mass of about 2 TeV freezes out after reheating.

Abstract

We discuss inflation and dark matter in the inert doublet model coupled non-minimally to gravity where the inert doublet is the inflaton and the neutral scalar part of the doublet is the dark matter candidate. We calculate the various inflationary parameters like $n_s$, $r$ and $P_s$ and then proceed to the reheating phase where the inflaton decays into the Higgs and other gauge bosons which are non-relativistic owing to high effective masses. These bosons further decay or annihilate to give relativistic fermions which are finally responsible for reheating the universe. At the end of the reheating phase, the inert doublet which was the inflaton enters into thermal equilibrium with the rest of the plasma and its neutral component later freezes out as cold dark matter with a mass of about 2 TeV.