Stellar Bounds on Light Spin-2 Particles in Bimetric Theories

TL;DR

This paper derives astrophysical bounds on light spin-2 particles in bimetric theories by analyzing stellar cooling, providing constraints on their properties that are competitive with existing limits and relevant for dark matter models.

Contribution

It introduces a method to compute stellar emission rates of light spin-2 particles and derives new bounds on their coupling and mass from stellar cooling observations.

Findings

Constraints exclude spin-2 particles with masses 5-30 eV.

Bounds are competitive with cosmological limits.

Results impact dark matter models involving light spin-2 particles.

Abstract

Using the bimetric formalism, we compute the production and emission rates of light spin-2 particles in non-degenerate stellar interiors through photoproduction and bremsstrahlung processes, including the effects of plasma screening. By comparing the resulting energy-loss rates with observational limits on stellar cooling, we derive bounds on the coupling strength and mass of the spin-2 particle. Assuming these particles are the dark matter of the Universe, the obtained constraints are competitive with existing astrophysical and cosmological limits, excluding a wide region of parameter space in the mass range 5-30 eV.