Improved Dark Photon Sensitivity from a Superconducting-Radio-Frequency-Cavity Experiment.

Area of Science:

• Particle Physics
• Cosmology
• Astrophysics

Background:

• Dark photons are hypothetical particles that interact weakly with ordinary matter.
• Previous experiments have searched for dark photons, but constraints remain limited.
• Understanding dark photons could shed light on dark matter and dark energy.

Purpose of the Study:

• To refine the exclusion bound for dark photons using data from the Dark SRF pathfinder run.
• To establish a world-leading laboratory constraint on non-dark-matter dark photons.
• To set the most stringent laboratory-based limit on the photon mass.

Main Methods:

• Improved theoretical modeling of frequency instability in high-quality resonant experiments.
• Analysis of data from the Dark SRF pathfinder run.
• Calculation of exclusion bounds and signal-to-noise ratios.

Main Results:

• An order of magnitude stronger exclusion bound for dark photons compared to previous results.
• A signal-to-noise ratio that is 4 orders of magnitude larger than previously reported.
• The best laboratory-based limit on the photon mass (m_{γ}<2.9×10^{-48} g) for masses below 6 μeV.

Conclusions:

• The Dark SRF pathfinder run provides the most stringent constraints on dark photons to date.
• Improved theoretical modeling is crucial for advancing resonant experiment sensitivity.
• This work significantly advances the search for new physics beyond the Standard Model.