The Radion as a Dark Matter Candidate

TL;DR

This paper explores a class of Randall-Sundrum models with spontaneous scale invariance breaking, proposing a light radion as a viable dark matter candidate consistent with current experimental bounds.

Contribution

It demonstrates that radions with masses below 1 KeV can serve as dark matter, with suppressed couplings and long lifetimes, within a specific class of RS models.

Findings

Radion can be a dark matter candidate with mass $ extless$ 1 KeV.

Radion lifetime exceeds the age of the universe.

Experimental bounds from LHC, gravity tests, and ALP searches are compatible with radion dark matter.

Abstract

I study a class of Randall-Sundrum (RS) models with Spontaneous Breaking of Scale Invariance (SBSI). This class of models implements the Contino-Pomarol-Rattazzi (CPR) mechanism to achieve SBSI through the small running of an external close-to-marginal scale-breaking operator that leads to a light dilaton/radion with couplings to matter suppressed by the small running. I show that for radion masses $\lesssim 1$ KeV, it can serve as a Dark Matter (DM) candidate, with a lifetime longer than the age of the universe, and show that the experimental bounds from LHC, Non-Newtonian Gravity and Axion-Like Particle (ALP) searches allow for the existence of such a radion.