Observational constraints on massive gravity

TL;DR

This paper investigates the cosmological implications of ghost-free massive gravity, analyzing its solutions and confronting them with observational data to constrain model parameters and graviton mass.

Contribution

It provides a detailed analysis of cosmological solutions in massive gravity and assesses their compatibility with current observational data.

Findings

Model parameters $oldsymbol{eta_3}$ and $oldsymbol{eta_4}$ are unconstrained by background data.

Graviton mass is approximately the current Hubble constant when $oldsymbol{eta_3=eta_4=0}$.

Graviton mass can be arbitrarily small in the most general case.

Abstract

The ghost free massive gravity modified Friedmann equations at cosmic scale and provided an explanation of cosmic acceleration without dark energy. We analyzed the cosmological solutions of the massive gravity in detail and confronted the cosmological model with current observational data. We found that the model parameters $\alpha_3$ and $\alpha_4$ which are the coefficients of the third and fourth order nonlinear interactions cannot be constrained by current data at the background level. The mass of graviton is found to be the order of current Hubble constant if $\alpha_3=\alpha_4=0$, and the mass of graviton can be as small as possible in the most general case.