Search for Dark Photons with Superconducting Radio Frequency Cavities

Area of Science:

• Experimental Particle Physics
• Astroparticle Physics
• Cosmology

Background:

• Dark photons are hypothetical particles that could constitute dark matter.
• Previous searches for dark photons have limitations in sensitivity and parameter space coverage.
• Superconducting radio frequency (SRF) cavities offer potential for enhanced sensitivity in dark photon detection.

Purpose of the Study:

• To conduct the first "light-shining-through-wall" (LSW) search for dark photons utilizing SRF cavities.
• To improve sensitivity and explore new parameter space for dark photons.
• To establish new exclusion limits on dark photon properties.

Main Methods:

• Utilized two high-quality-factor SRF cavities (Dark SRF) operating at 1.3 GHz in an LSW experimental setup.
• Developed specialized calibration and measurement protocols for the high-Q SRF cavities.
• Searched for longitudinal photon polarization to set limits on the standard model photon mass.

Main Results:

• Established a new exclusion limit for kinetic mixing of dark photons down to ε=1.6×10^{-9}.
• Provided the world's best constraints on dark photons in the mass range of 2.1×10^{-7}-5.7×10^{-6} eV.
• Achieved a competitive lab-based limit on the standard model photon mass.

Conclusions:

• SRF cavities are a promising technology for future LSW experiments.
• The experiment successfully demonstrated the enabling role of SRF cavities in LSW searches.
• Further improvements in SRF cavity technology can lead to even greater sensitivity in dark matter searches.