Freeze-in from Preheating

TL;DR

This paper investigates how dark matter can be produced during the reheating phase after inflation, comparing different calculation methods and energy distributions to determine conditions for matching observed dark matter density.

Contribution

It introduces a comparison between perturbative and non-perturbative calculations of radiation energy density during preheating, analyzing their impact on dark matter freeze-in relic density.

Findings

Dark matter relic density can be achieved via freeze-in from preheating across various masses.

Different energy distribution assumptions significantly affect relic density calculations.

Both thermal and non-thermal scenarios are viable for producing observed dark matter abundance.

Abstract

We consider the production of dark matter during the process of reheating after inflation. The relic density of dark matter from freeze-in depends on both the energy density and energy distribution of the inflaton scattering or decay products composing the radiation bath. We compare the perturbative and non-perturbative calculations of the energy density in radiation. We also consider the (likely) possibility that the final state scalar products are unstable. Assuming either thermal or non-thermal energy distribution functions, we compare the resulting relic density based on these different approaches. We show that the present-day cold dark matter density can be obtained through freeze-in from preheating for a large range of dark matter masses.