Cavity as Radio Telescope for Galactic Dark Photon

TL;DR

This paper proposes using superconducting radio-frequency cavities as resonant detectors to search for galactic dark photons, setting new limits on their interaction with electromagnetic photons and opening new avenues for dark matter detection.

Contribution

It introduces a novel cavity-based detection framework for dark photons, utilizing Earth's rotation and polarization dependence to improve search sensitivity.

Findings

Established the effectiveness of superconducting cavities as dark photon telescopes.

Set the most stringent limits on dark photon-electromagnetic photon kinetic mixing.

Demonstrated the potential of multi-messenger astronomy in dark matter searches.

Abstract

Dark photons, as a minimal extension of the Standard Model through an additional Abelian gauge group, may propagate relativistically across the galaxy, originating from dark matter decay or annihilation, thereby contributing to a galactic dark photon background. The generation of dark photons typically favors certain polarization modes, which are dependent on the interactions between dark matter and dark photons. We introduce a framework in which a resonant cavity is utilized to detect and differentiate these polarizations, leveraging the daily variation in expected signals due to the anisotropic distribution of dark photons and the rotation of the Earth. We conduct an experimental search using superconducting radio-frequency cavities, noted for their exceptionally high quality factors, proving them to be effective telescopes for observing galactic dark photons. This approach establishes the most stringent limits yet on the kinetic mixing coefficient between dark photons and electromagnetic photons, thereby unveiling a novel avenue for the indirect search for dark matter via multi-messenger astronomy.