Near-Quantum-Noise Axion Dark Matter Search at CAPP around
Jinsu Kim (Department of Physics, KAIST, Daejeon 34141, Republic of Korea, Center for Axion and Precision Physics Research (CAPP), IBS, Daejeon 34051, Republic of Korea); Ohjoon Kwon (Center for Axion and Precision Physics Research (CAPP), IBS, Daejeon 34051, Republic of Korea); Çağlar Kutlu (Department of Physics, KAIST, Daejeon 34141, Republic of Korea, Center for Axion and Precision Physics Research (CAPP), IBS, Daejeon 34051, Republic of Korea); Woohyun Chung (Center for Axion and Precision Physics Research (CAPP), IBS, Daejeon 34051, Republic of Korea); Andrei Matlashov (Center for Axion and Precision Physics Research (CAPP), IBS, Daejeon 34051, Republic of Korea); et al - Show all 12 authors
We report the results of an axion dark matter search over an axion mass range of . 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.