Massive graviton dark matter with environment dependent mass: A natural explanation of the dark matter-baryon ratio

TL;DR

This paper presents a bimetric theory model with a chameleon field where the environment-dependent mass of the massive graviton naturally explains the observed dark matter-baryon ratio through dynamic energy transfer.

Contribution

It introduces a novel bimetric framework with a non-minimally coupled chameleon field that dynamically adjusts the dark matter-baryon ratio, independent of initial conditions.

Findings

The model achieves the observed dark matter-baryon ratio dynamically.

Energy transfer via the chameleon field explains the ratio without fine-tuning.

The framework links dark matter and dark energy through gravitational degrees of freedom.

Abstract

We propose a scenario that can naturally explain the observed dark matter-baryon ratio in the context of bimetric theory with a chameleon field. We introduce two additional gravitational degrees of freedom, the massive graviton and the chameleon field, corresponding to dark matter and dark energy, respectively. The chameleon field is assumed to be non-minimally coupled to dark matter, i.e., the massive graviton, through the graviton mass terms. We find that the dark matter-baryon ratio is dynamically adjusted to the observed value due to the energy transfer by the chameleon field. As a result, the model can explain the observed dark matter-baryon ratio independently from the initial abundance of them.