Warm dark matter from a gravitational freeze-in in extra dimensions

TL;DR

This paper explores a gravitational freeze-in mechanism in extra dimensions for producing warm dark matter, highlighting a parameter space consistent with observations but difficult to test terrestrially, with potential astrophysical signatures.

Contribution

It introduces a minimal five-dimensional model where gravitational interactions produce dark matter, expanding the understanding of dark matter genesis in extra-dimensional frameworks.

Findings

Large parameter space yields correct relic density.

Many scenarios produce warm dark matter.

Scenario is challenging to test in laboratory experiments.

Abstract

We study the freeze-in of gravitationally interacting dark matter in extra dimensions. Focusing on a minimal dark matter candidate that only interacts with the SM via gravity in a five-dimensional model we find that a large range of dark matter and Kaluza-Klein graviton masses can lead to the observed relic density. The preferred values of the masses and the strength of the interaction make this scenario very hard to test in terrestrial experiments. However, significant parts of the parameter space lead to warm dark matter and can be tested by cosmological and astrophysical observations.