SRF Cavity As Galactic Dark Photon Telescope

Dark photons, aside from constituting non-relativistic dark matter, can alsobe generated relativistically through the decay or annihilation of other darkmatter candidates, contributing to a galactic dark photon background. Theproduction of dark photons tends to favor specific polarization modes,determined by the microscopic coupling between dark matter and dark photons. Weleverage data obtained from previous searches for dark photon dark matter usinga superconducting radio-frequency cavity to explore galactic dark photonfluxes. The interplay of anisotropic directions and Earth's rotation introducesa diurnal modulation of signals within the cavities, manifesting distinctvariation patterns for longitudinal and transverse modes. Our findingshighlight the efficacy of superconducting radio-frequency cavities,characterized by significantly high-quality factors, as powerful telescopes fordetecting galactic dark photons, unveiling a novel avenue in the indirectsearch for dark matter through multi-messenger astronomy.