Energetic axion-like particle production in galaxies

TL;DR

This paper investigates how energetic axion-like particles produced in galaxies could form a detectable isotropic background, potentially observable by current particle experiments, and assesses their contribution to the universe's ALP content.

Contribution

It introduces a model for energetic ALP production in galaxies and evaluates their detectability as an isotropic background in existing experiments.

Findings

Energetic ALPs can form a measurable isotropic background.

Galactic ALP production may contribute significantly to the universe's ALP content.

Current experiments could detect this ALP background under certain conditions.

Abstract

Relativistic axion-like particles (ALPs) originating from the stellar interiors, along with the ones coming from photon-ALP mixing in the galactic magnetic fields, contribute together to make an energetic component of the ALP content of the universe. Considering an isotropic distribution of cosmic gamma rays, it is examined if these high energy axion-like particles could constitute a measurable isotropic "background" for helioscope-type and existing large general-purpose particle experiments, taking into account their sensitivity.