Massive Gravitons as Feebly Interacting Dark Matter Candidates

TL;DR

This paper proposes that massive spin-2 gravitons, produced via a chiral enhancement mechanism below the electroweak scale, are viable sub-MeV dark matter candidates consistent with small-scale galaxy structure observations.

Contribution

It introduces a new chiral enhancement effect in graviton production cross sections, enabling massive gravitons to serve as dark matter within a Randall-Sundrum model.

Findings

Massive gravitons can be produced via freeze-in mechanism.

Parameter space where gravitons account for dark matter density.

Gravitons in the keV-MeV range fit small-scale structure data.

Abstract

We detailed our discovery of a chiral enhancement in the production cross sections of massive spin-2 gravitons, below the electroweak symmetry breaking scale, that makes them ideal dark matter candidates for the freeze-in mechanism. The result is independent of the physics at high scales, and points toward masses in the keV- MeV range. The graviton is, therefore, a sub-MeV dark matter particle, as favored by the small scale galaxy structures. We apply the novel calculation to a Randall-Sundrum model with multiple branes, showing a significant parameter space where the first two massive gravitons saturate the dark matter relic density.