Supernova Bounds on the Dark Photon Using its Electromagnetic Decay

TL;DR

This paper investigates how supernova observations, especially SN1987A, impose strong constraints on the properties of hypothetical dark photons that can decay electromagnetically, surpassing previous bounds.

Contribution

It introduces new supernova-based bounds on dark photon mass and mixing parameters, significantly tightening existing constraints in the 5-20 MeV range.

Findings

Supernova SN1987A data yields bounds on dark photon parameters.

Dark photon decay signatures can be constrained by cosmological and supernova observations.

Supernova bounds are up to 300 times stronger than previous energy loss limits.

Abstract

The hypothetical massive dark photon ($\gamma'$) which has kinetic mixing with the SM photon can decay electromagnetically to $e^+e^-$ pairs if its mass $m$ exceeds $2m_e$ and otherwise into three SM photons. These decays yield cosmological and supernovae associated signatures. We briefly discuss these signatures, particularly in connection with the supernova SN1987A and delineate the extra constraints that may then arise on the mass and mixing parameter of the dark photon. In particular, we find that for dark photon mass $m_{\gamma'}$ in the 5-20 MeV range, arguments based on supernova 1987A observations lead to a bound on $\epsilon$ which is about 300 times stronger than the presently existing bounds based on energy loss arguments.