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轻子风味数违反衰变过程，一个介子衰变为一个正电子和一个光子。这一过程是基本粒子标准模型所严格禁止的，而这一过程的发现，给了我们一个超越标准模型的粒子物理新世界的信号。实验概念是基于测量光子能量、位置和定时的液态氙闪烁量热计和测量正电子动量的COBRA光谱仪两种创新思想。为了使上述实验成为可能，已经实施了几个开发方案。首先，研制了一种新型光电倍增管，用于在-100℃低温下检测液态氙的闪烁光子（波长为175 nm）。建立了一个包含32个光电倍增管的小型测试量热计，并用于验证液体氙量热计的预期性能。其次，研制了脉管制冷机，直接液化了大量的氙气。1999年5月，与其他研究一起撰写并提交给瑞士Paul Sherrer研究所。该建议于1999年7月被研究所接受。目前，正在研究进一步的细节。

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.