Near-quantum-limited axion dark matter search with the ORGAN experiment around 26 $\mu$eV

TL;DR

The ORGAN experiment achieved near-quantum-limited sensitivity in searching for axion dark matter around 26 μeV, setting the most stringent exclusion limits on axion-photon coupling in this mass range.

Contribution

This work reports the first near-quantum-limited axion search with improved sensitivity and new exclusion limits using advanced low-noise amplification and resonator techniques.

Findings

Set the most sensitive exclusion limits on axion-photon coupling at 25.45-26.27 μeV.

Operated at millikelvin temperatures with a flux-driven Josephson parametric amplifier.

Achieved a coupling sensitivity of |g_{aγγ}| ≥ 2.8×10^{-13} at 95% confidence.

Abstract

The latest result from the ORGAN experiment, an axion haloscope is presented. This iteration of the experiment operated at millikelvin temperatures using a flux-driven Josephson parametric amplifier for reduced noise, along with various other improvements over previous iterations. Covering the $25.45 - 26.27\,\mu\text{eV}$ ($6.15-6.35$ GHz) mass (frequency) range, this near-quantum limited phase of ORGAN employs a conducting rod resonator and a 7-T solenoidal magnet to place the most sensitive exclusion limits on axion-photon coupling in the range to date, with $|g_{a\gamma\gamma}| \gtrsim 2.8\times10^{-13}$ at a 95\% confidence level.