We report on a search for axion dark matter in the frequency range near 5.9 GHz, conducted using the haloscope technique. The experiment employed an 8-cell microwave resonator designed to extend the accessible frequency range by a multi-fold factor relative to conventional single-cell configurations, while maintaining a large detection volume. To enhance sensitivity, a flux-driven Josephson parametric amplifier (JPA) operating near the quantum noise limit was utilized, together with a sideband-summing method that coherently combines mirrored spectral components generated by the JPA. Data were acquired over the frequency range 5.83-5.94 GHz. With no statistically significant excess observed, we exclude axion-photon couplings gaγγ down to 1.2×10−14 GeV−1 at a 90% confidence level. The achieved sensitivity approaches the KSVZ benchmark prediction, setting the most stringent limits to date in this range.
@article{arxiv.2507.04344,
title = {Probing KSVZ Axion Dark Matter near 5.9 GHz Using a 8-Cell Cavity Haloscope},
author = {Saebyeok Ahn and Caglar Kutlu and Soohyung Lee and SungWoo Youn and Sergey V. Uchaikin and Sungjae Bae and Junu Jeong and Arjan F. van Loo and Yasunobu Nakamura and Seongjeong Oh and Jihn E. Kim and Yannis K. Semertzidis},
journal= {arXiv preprint arXiv:2507.04344},
year = {2025}
}