Search for 70  μeV Dark Photon Dark Matter with a Dielectrically Loaded Multiwavelength Microwave Cavity

Area of Science:

• Particle Physics
• Cosmology
• Astrophysics

Background:

• Microwave cavities are used to detect bosonic dark matter candidates with masses around a few micro-electronvolts (μeV).
• Standard half-wavelength cavities face reduced sensitivity at higher masses due to decreased detection volume.
• A large detection volume is crucial for enhancing the sensitivity of dark matter searches.

Purpose of the Study:

• To explore a new method for detecting bosonic dark matter using a tunable, dielectrically loaded cavity operating at a higher-order mode.
• To mitigate the volume reduction issue faced by traditional cavities at higher dark matter masses.
• To expand the search range for dark matter candidates in the micro-electronvolt mass range.

Main Methods:

• Utilizing the Axion Dark Matter Experiment (ADMX)-Orpheus, a tunable, dielectrically loaded cavity operating at a higher-order mode.
• Performing an inaugural experimental run to search for dark photon dark matter.
• Excluding a specific range of kinetic mixing angles for dark photon dark matter.

Main Results:

• The ADMX-Orpheus experiment successfully operated a tunable, dielectrically loaded cavity at a higher-order mode, maintaining a large detection volume.
• The inaugural run excluded dark photon dark matter with kinetic mixing angle χ > 10⁻¹³.
• The search was conducted between 65.5 μeV (15.8 GHz) and 69.3 μeV (16.8 GHz).

Conclusions:

• The ADMX-Orpheus experiment demonstrates a successful approach to increasing the detection volume of microwave cavity experiments for higher-mass dark matter.
• This marks the highest-frequency tunable microwave cavity dark matter search to date.
• The results provide new constraints on dark photon dark matter models.