The meV mass frontier of axion physics

TL;DR

This paper investigates the implications of axions with a mass of a few meV on white dwarf cooling, supernova energy loss, and the potential for detection via helioscopes, highlighting their role in astrophysics and dark matter.

Contribution

It connects axion properties inferred from white dwarf cooling to supernova energy emission and proposes a new detection approach with next-generation helioscopes.

Findings

Axions with g_{ae} ~ 10^-13 can explain white dwarf cooling.

Supernovae could emit significant axion energy, forming a diffuse background.

Next-generation helioscopes may detect axions with these parameters.

Abstract

We explore consequences of the idea that the cooling speed of white dwarfs can be interpreted in terms of axion emission. In this case the Yukawa coupling to electrons has to be g_{ae} 10^-13, corresponding to an axion mass of a few meV. Axions then provide only a small fraction of the cosmic cold dark matter, whereas core-collapse supernovae release a large fraction of their energy in the form of axions. We estimate the diffuse supernova axion background (DSAB) in the universe, consisting of 30 MeV-range axions with a radiation density comparable to the extra-galactic background light. The DSAB would be challenging to detect. However, axions with white-dwarf inspired parameters can be accessible in a next generation axion helioscope.