AI 中文总结
本研究利用微热量计通过μ介子原子光谱法测量$^9$Be的核电荷半径，测量了$2p\to1s$跃迁能量，结果比之前精确30倍，所提取的核电荷半径比常用值精确2.4倍，是首次用该方法确定核电荷半径。
AI 中文摘要
使用金属磁热量计测量了μ介子$^9$Be中$2p\to1s$的跃迁能量，结果为$E_{2p\to 1s}=33391.48(34)$eV。该结果比之前最佳测量精确30倍，可提取相应核电荷半径$r_c(^9$Be$)=2.5506(51)$fm，比基于电子散射的常用值精确2.4倍，相差2.3倍综合不确定性。此测量是首次用微热量计通过μ介子X射线光谱法确定核电荷半径。
英文摘要
The $2p\to1s$ transition energy in muonic $^9$Be was measured using a metallic magnetic calorimeter, resulting in $E_{2p\to 1s}=33\,391.48(34)\,$eV. The result is 30 times more precise than the previous best measurement and enables the extraction of the corresponding nuclear charge radius $r_c($$^9$Be$)=2.5506(51)\,$fm. It is $2.4$ times more precise than the commonly used value based on electron scattering and differs from it by $2.3$ times the combined uncertainties. This measurement represents the first determination of a nuclear charge radius using muonic x-ray spectroscopy with microcalorimeters.
