Search for 70 \mu eV Dark Photon Dark Matter with a Dielectrically-Loaded Multi-Wavelength Microwave Cavity

TL;DR

This paper reports on a novel microwave cavity detector that uses a dielectrically-loaded design to effectively search for dark photon dark matter in the 65.5 to 69.3 microelectronvolt range, achieving the highest frequency sensitivity to date.

Contribution

The study introduces a tunable, dielectrically-loaded cavity operating at higher-order modes, enabling larger detection volumes at higher frequencies for dark matter searches.

Findings

Excluded dark photon kinetic mixing angles > 10^{-13} in the 65.5-69.3 μeV range

Achieved highest-frequency tunable microwave cavity dark matter search

Demonstrated effective mitigation of volume reduction at higher masses

Abstract

Microwave cavities have been deployed to search for bosonic dark matter candidates with masses of a few $\mu$eV. However, the sensitivity of these cavity detectors is limited by their volume, and the traditionally-employed half-wavelength cavities suffer from a significant volume reduction at higher masses. ADMX-Orpheus mitigates this issue by operating a tunable, dielectrically-loaded cavity at a higher-order mode, which allows the detection volume to remain large. The ADMX-Orpheus inaugural run excludes dark photon dark matter with kinetic mixing angle $\chi > 10^{-13}$ between 65.5 $\mu$eV (15.8 GHz) and 69.3 $\mu$eV (16.8GHz), marking the highest-frequency tunable microwave cavity dark matter search to date.