Supernova constraints on an axion-photon-dark photon interaction

TL;DR

This paper investigates how supernova observations constrain the interaction between axions, photons, and dark photons, revealing unique features in the bounds due to particle mass and mode coupling differences.

Contribution

It introduces novel supernova constraints on axion-dark photon couplings, highlighting how particle mass and mode polarization affect these bounds.

Findings

Supernova bounds weaken exponentially for sufficiently massive particles.

Longitudinal dark photon modes can cause cooling even if transverse modes are trapped.

Constraints appear as two independent bounds for light dark photons.

Abstract

We present the supernova constraints on an axion-photon-dark photon coupling, which can be the leading coupling to dark sector models and can also lead to dramatic changes to axion cosmology. We show that the supernova bound on this coupling has two unusual features. One occurs because the scattering that leads to the trapping regime converts axions and dark photons into each other. Thus, if one of the two new particles is sufficiently massive, both production and scattering become suppressed and the bounds from bulk emission and trapped (area) emission both weaken exponentially and do not intersect. The other unusual feature occurs because for light dark photons, longitudinal modes couple more weakly than transverse modes do. Since the longitudinal mode is more weakly coupled, it can still cause excessive cooling even if the transverse mode is trapped. Thus, the supernova constraints for massive dark photons look like two independent supernova bounds super-imposed on top of each other.