Speaker
Description
Axion relic pockets are phase-transition remnants consisting of regions of false vacuum stabilised from collapse by a hot axion gas. Axion relic pockets can comprise dark matter, but little is known about their phenomenology. We consider trapped axions coupled to electromagnetism and show that axion-photon conversion occurs in atomic electric fields, leading to high-energy electromagnetic cascades that may be detectable by neutrino, cosmic-ray, and dark-matter experiments. Calculating the interaction rate requires accounting for the pocket's compactness and spherical geometry. The distribution of electromagnetic showers is inherently isotropic, and upward-going showers provide a smoking-gun signal for the model. Using recent data from the IceCube neutrino telescope, we derive the first limits on axion relic pockets. We also comment on the prospects for detecting axion relic pockets with atmospheric detectors, including fluorescence detection by the Pierre Auger Observatory and radio Cherenkov detection by balloon-borne payloads, such as ANITA and PUEO. These results open a new observational window on dark matter and motivate dedicated searches for the associated electromagnetic showers across existing and forthcoming high-energy facilities.
| arXiv number (if applicable) | 2507.01191 |
|---|---|
| Position | PhD student |