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

Understand

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.