Inflaton Dark Matter

TL;DR

This paper proposes a minimal extension of the Standard Model where a single scalar field acts as both the inflaton and dark matter, with its viability depending on thermal production near half the Higgs mass.

Contribution

It introduces a simple model unifying inflation and dark matter using a single scalar field with detailed analysis of its production mechanisms and viability.

Findings

Inflaton dark matter is viable only in the thermal production scenario.

The inflaton mass must be near half the Higgs mass for the model to work.

Quantum effects induce a non-minimal coupling to gravity facilitating inflation.

Abstract

We discuss a minimal extension of the Standard Model (SM) where a single real scalar field serves as both inflaton and dark matter. The corresponding Lagrangian contains the renormalizable interactions of the inflaton field. Quantum effects generally induce a non-minimal coupling to gravity which facilitates inflation consistent with the PLANCK constraints. A large fraction of the inflaton quanta produced after inflation must be converted into the SM radiation reheating the Universe and the rest remains dark matter today. We consider thermal and non-thermal production of inflaton dark matter. In the non-thermal case, we take into account collective effects with the help of lattice simulations. Combining analytic and numerical results with the unitarity consideration, we find that the inflaton dark matter model is viable only in the thermal case where the inflaton mass is near half the Higgs mass.