First Scan Search for Dark Photon Dark Matter with a Tunable Superconducting Radio-Frequency Cavity

• Published in: Physical review letters 2024-07, Vol.133 (2), p.021005, Article 021005
• Main Authors: Tang, Zhenxing, Wang, Bo, Chen, Yifan, Zeng, Yanjie, Li, Chunlong, Yang, Yuting, Feng, Liwen, Sha, Peng, Mi, Zhenghui, Pan, Weimin, Zhang, Tianzong, Jin, Yirong, Hao, Jiankui, Lin, Lin, Wang, Fang, Xie, Huamu, Huang, Senlin, Shu, Jing
• Format: Article
• Language: English
• ISSN: 0031-9007; 1079-7114; 1079-7114
• DOI: 10.1103/PhysRevLett.133.021005

Dark photons have emerged as promising candidates for dark matter, and their search is a top priority in particle physics, astrophysics, and cosmology. We report the first use of a tunable niobium superconducting radio-frequency cavity for a scan search of dark photon dark matter with innovative data analysis techniques. We mechanically adjusted the resonant frequency of a cavity submerged in liquid helium at a temperature of 2 K, and scanned the dark photon mass over a frequency range of 1.37 MHz centered at 1.3 GHz. Our study leveraged the superconducting radio-frequency cavity's remarkably high quality factors of approximately 10^{10}, resulting in the most stringent constraints to date on a substantial portion of the exclusion parameter space on the kinetic mixing coefficient ε between dark photons and electromagnetic photons, yielding a value of ε