Study of High Intensity Stopping Muon Beams and Experimental Apparatuses for μィイD1+ィエD1 →eィイD1+ィエD1+γ Experiment

设计了一个实验来改进和识别违反衰变过程的轻子味道数，一个介子衰变为一个正电子和一个光子。这个过程被基本粒子的标准模型严格禁止，而这个过程的识别为我们提供了一个超越标准模型的粒子物理新世界的信号。实验的概念基于两个创新的想法：用于测量光子的能量、位置和时间的液体氙闪动量热计和用于测量正电子动量的COBRA能谱仪。为了使上述实验成为可能，已经实施了几个开发计划。首先，研制了一种新型光电倍增管，用于探测低温下液体氙气的闪烁光子(波长为175 nm)，温度为-100℃。建立了一个32个光电倍增管的小型测试量热计，并用它来验证液体氙量热计的预期性能。其次，研制了直接液化大量氙气的脉冲管制冷机，并与其他研究一起，于1999年5月向瑞士保罗·谢雷尔研究所提交了实验建议书。这项建议于1999年7月被学院接纳。目前，进一步的细节正在研究中。

An experiment was designed to improve and identify a lepton flavor number violating decay process, a muon decay into a positron and a photon. The process is severely prohibited by the standard model of the elementary particle, and the identification of the process gives us a signal of the new world of the particle physics, beyond the standard model.The concept of the experiment is based on two innovative ideas, liquid xenon scintillation calorimeter for measuring energy, position and timing of photons and COBRA spectrometer for measuring momentum of positrons.Several development programs have been carried out to made the above experiment possible. Firstly, a new phtomultiplier tube was developed to detect the scintillation photons(wavelength of 175 nm) from liquid xenon at the low temperature of -100℃. A small test calorimeter with 32 photomultiplier tubes was built and used to confirm the expected performances of the liquid xenon calorimeter. Secondly, a pulse tube refrigerator was developed to directly liquefy the large amount of xenon gas.Together with other studies, and experimental proposal was written and submitted to Paul Sherrer Institute, Switzerland in May 1999. The proposal was accepted in July, 1999 by the Institute. Currently, further details are being studied.