AI 中文总结
J-PARC强子实验装置的研究团队建立μ20缪子束流方案，实现高动量高纯度缪子束，为日本该类束线运行提供可行性验证。
AI 中文摘要
我们在J-PARC强子实验装置的高动量强子束线（B-line）上建立并表征了一种新型高纯度缪子束流输送方案，命名为μ20。该方案通过束线直段内次级π介子的飞行中衰变产生 tertiary缪子，固有地抑制了母强子污染。在系统性能评估中，缪子束在下游探测器位置的独立强度达到1.7×10³粒子/束团，空间展宽（标准差σ）约为15 mm。利用铁吸收体进行的系统衰减分析验证了3 GeV/c缪子束模式的缪子纯度高达98.0±0.6%。至关重要的是，这项工作是日本实验装置中首次成功开展的高动量、高纯度缪子束线运行的可行性研究。
英文摘要
We have established and characterized a novel high-purity muon beam delivery scheme, designated as $μ$20, at the high-momentum hadron beamline (B-line) of the J-PARC Hadron Experimental Facility. This scheme delivers tertiary muons produced via the in-flight backward decays of secondary pions in the straight section of the beamline, inherently suppressing parent hadron contamination. In a systematic performance evaluation, the muon beam achieved a standalone intensity of $1.7\times10{^3}$ particles/spill with a spatial spread (standard deviation, $σ$) of approximately 15 mm at the downstream detector position. A systematic attenuation analysis utilizing an iron absorber verified a high muon purity of 98.0$\pm$0.6% for the 3 GeV/$c$ muon beam mode. Crucially, this work marks the first successful feasibility study of a high-momentum and high-purity muon beamline operation at an experimental facility in Japan.
