Crescini N, Alesini D, Braggio C, Carugno G, D'Agostino D, Di Gioacchino D, Falferi P, Gambardella U, Gatti C, Iannone G, Ligi C, Lombardi A, Ortolan A, Pengo R, Ruoso G, Taffarello L
INFN-Laboratori Nazionali di Legnaro, Viale dell'Università 2, 35020 Legnaro (PD), Italy.
Dipartimento di Fisica e Astronomia, Via Marzolo 8, 35131 Padova, Italy.
Phys Rev Lett. 2020 May 1;124(17):171801. doi: 10.1103/PhysRevLett.124.171801.
A ferromagnetic axion haloscope searches for dark matter in the form of axions by exploiting their interaction with electronic spins. It is composed of an axion-to-electromagnetic field transducer coupled to a sensitive rf detector. The former is a photon-magnon hybrid system, and the latter is based on a quantum-limited Josephson parametric amplifier. The hybrid system consists of ten 2.1 mm diameter yttrium iron garnet spheres coupled to a single microwave cavity mode by means of a static magnetic field. Our setup is the most sensitive rf spin magnetometer ever realized. The minimum detectable field is 5.5×10^{-19} T with 9 h integration time, corresponding to a limit on the axion-electron coupling constant g_{aee}≤1.7×10^{-11} at 95% C.L. The scientific run of our haloscope resulted in the best limit on dark matter axions to electron coupling constant in a frequency span of about 120 MHz, corresponding to the axion-mass range 42.4-43.1 μeV. This is also the first apparatus to perform a wide axion-mass scanning by only changing the static magnetic field.
一种铁磁轴子探测仪通过利用轴子与电子自旋的相互作用来搜寻轴子形式的暗物质。它由一个与灵敏射频探测器耦合的轴子 - 电磁场换能器组成。前者是一个光子 - 磁振子混合系统，后者基于量子极限约瑟夫森参量放大器。该混合系统由十个直径为2.1毫米的钇铁石榴石球体组成，通过静磁场耦合到单个微波腔模式。我们的装置是有史以来最灵敏的射频自旋磁力计。在9小时积分时间下，最小可探测场为5.5×10⁻¹⁹ T，对应于在95%置信水平下轴子 - 电子耦合常数gₐₑₑ≤1.7×10⁻¹¹。我们探测仪的科学运行在约120 MHz的频率范围内得出了暗物质轴子与电子耦合常数的最佳限制，对应于轴子质量范围42.4 - 43.1 μeV。这也是首个仅通过改变静磁场就能进行宽轴子质量扫描的装置。
