发表机构
School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University（北京大学物理学院和核物理与技术国家重点实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究评估了HIAF上利用缪子束流搜索奇异衰变μ→eX0的可行性，通过优化探测器截断抑制背景，在95%置信水平下将分支比上限设为1×10⁻⁵，实现先进灵敏度。
AI 中文摘要
我们针对高流强重离子加速器装置（HIAF）上的缪子束流，对奇异缪子衰变搜索进行了详细的可行性研究。对于衰变道μ→eX0，其中X0代表具有轻子味破坏（LFV）耦合的新玻色子，当X0的质量接近缪子质量时，产生的电子携带极低的能量，这使得探测具有挑战性。然而，HIAF的高能束流可以将这些电子提升到可测量的能量范围。本文提出的探测器系统包括用于粒子鉴别（PID）的前端闪烁体，以及由RPC堆栈（用于追踪衰变产物）和闪烁体（用于能量测量）组成的主探测器。利用信号电子低动量和发射角小的运动学特性，我们在RPC探测器上采用优化的动量和角度接受度截断，以有效抑制背景事件。通过这一策略，我们在95%置信水平下获得了奇异缪子衰变分支比的上限为1×10⁻⁵，达到了最先进的灵敏度。
英文摘要
We present a detailed feasibility study of exotic muon decay searches using the muon beam at the High Intensity heavy-ion Accelerator Facility (HIAF). For the decay channel mu to eX0, where X0 denotes a new boson featuring LFV couplings, the produced electron carries very low energy when the mass of X0 approaches the muon mass, making detection challenging. Nevertheless, the high-energy beam at HIAF can boost these electrons up to a measurable energy range. The detector system proposed here comprises front-end scintillators for particle identification (PID) and a main detector consisting of an RPC stack to track decay products and a scintillator for energy measurement. Leveraging the kinematic properties of low momenta and small emission angles of signal electrons, we employ optimized momentum and angular acceptance cuts on the RPC detector to efficiently suppress background events. With this strategy, we obtain an upper limit of 1e-5 on the branching ratio of the exotic muon decay at 95% confidence level, achieving state-of-the-art sensitivity.
Comments7 pages, 8 figures
