Transient and Diffuse Axions: Beyond Dark Matter

by Joshua Eby (Stockholm University)

Thursday 27 Jun 2024, 15:00 → 16:30 Europe/Berlin

seminar room 3 (bldg. 1b)

Axions and other light scalar particles are well-motivated as a solution to fine-tuning problems in the Standard Model and as candidates for dark matter. In this talk, I will discuss prospects for discovering axions from relativistic emission in astrophysical processes, including Standard Model sources like neutron stars or supernovae, as well as from bound states in the dark sector in a wide range of models. Relativistic emission from such bursts can be directly searched for in traditional axion direct-detection experiments. Bursts occurring during or after galactic structure formation can also lead to a build-up of a diffuse axion background (DaB), which is analogous to the diffuse supernova neutrino background. Astrophysical searches for photon excesses, especially gamma-ray searches like Fermi-LAT and COMPTEL, are a prime way to search for the DaB, as DaB axions would readily decay or convert to photons in galactic magnetic fields.