Department of Physics, KAIST, Daejeon 34141, Republic of Korea.
Center for Axion and Precision Physics Research (CAPP), IBS, Daejeon 34051, Republic of Korea.
Phys Rev Lett. 2023 Mar 3;130(9):091602. doi: 10.1103/PhysRevLett.130.091602.
We report the results of an axion dark matter search over an axion mass range of 9.39-9.51 μeV. A flux-driven Josephson parametric amplifier (JPA) was added to the cryogenic receiver chain. A system noise temperature of as low as 200 mK was achieved, which is the lowest recorded noise among published axion cavity experiments with phase-insensitive JPA operation. In addition, we developed a two-stage scanning method which boosted the scan speed by 26%. As a result, a range of two-photon coupling in a plausible model for the QCD axion was excluded with an order of magnitude higher in sensitivity than existing limits.
我们报告了在轴子质量范围为 9.39-9.51μeV 内进行轴子暗物质搜索的结果。在低温接收链中增加了通量驱动的约瑟夫森参量放大器 (JPA)。实现了低至 200mK 的系统噪声温度，这是具有相敏 JPA 操作的已发表轴子腔实验中记录到的最低噪声。此外，我们还开发了一种两阶段扫描方法，将扫描速度提高了 26%。结果，排除了在 QCD 轴子的一个合理模型中的双光子耦合范围，灵敏度比现有极限高一个数量级。
