Axion Dark Matter Search around 4.55 $\mu$eV with Dine-Fischler-Srednicki-Zhitnitskii Sensitivity

We report an axion dark matter search at Dine-Fischler-Srednicki-Zhitnitskii sensitivity with the CAPP-12TB haloscope, assuming axions contribute 100% of the local dark matter density. The search excluded the axion–photon coupling $g_{a\gamma \gamma }$ down to about $6.2\times {10}^{-16}$ GeV${}^{-1}$ over the axion mass range between 4.51 and 4.59 $\mu$eV at a 90% confidence level. The achieved experimental sensitivity can also exclude Kim-Shifman-Vainshtein-Zakharov axion dark matter that makes up just 13% of the local dark matter density. The CAPP-12TB haloscope will continue the search over a wide range of axion masses.