Stellar Recipes for Axion Hunters

TL;DR

This paper investigates the possibility that stellar energy losses are due to axions with a mass around 10 meV, fitting astrophysical data and discussing detection prospects with future experiments.

Contribution

It provides a comprehensive analysis of axion models fitting stellar loss data and evaluates the potential for future experiments to detect axions in this mass range.

Findings

Both DFSZ and KSVZ models fit the data well.

Preferred axion mass around 10 meV.

Future experiments can probe this mass range.

Abstract

There are a number of observational hints from astrophysics which point to the existence of stellar energy losses beyond the ones accounted for by neutrino emission. These excessive energy losses may be explained by the existence of a new sub-keV mass pseudoscalar Nambu--Goldstone boson with tiny couplings to photons, electrons, and nucleons. An attractive possibility is to identify this particle with the axion -- the hypothetical pseudo Nambu--Goldstone boson predicted by the Peccei--Quinn solution to the strong CP problem. We explore this possibility in terms of a DFSZ-type axion and of a KSVZ-type axion/majoron, respectively. Both models allow a good global fit to the data, prefering an axion mass around 10 meV. We show that future axion experiments -- the fifth force experiment ARIADNE and the helioscope IAXO -- can attack the preferred mass range from the lower and higher end, respectively. An axion in this mass range can also be the main constituent of dark matter.