标题： 首次逐事件识别液氩中亚兆电子伏粒子的切连科夫辐射 显示英文标题

标题： First Event-by-Event Identification of Cherenkov Radiation from Sub-MeV Particles in Liquid Argon

摘要： 这封信报告了Coherent CAPTAIN-Mills (CCM)实验在高闪烁光产率液态氩（LAr）探测器中对亚兆电子伏特电子的切连科夫光进行逐事件观测。 位于洛斯阿拉莫斯国家实验室的CCM200探测器，用200个8英寸光电倍增管（PMTs）来测量7吨（有效体积）的LAr，其中80%的PMTs涂有波长转换材料，其余20%未涂层。 在事件的即时时间区域，定义为相对于事件开始时间$t=0$的$-6 \leq t \leq 0$ ns内，未涂层的PMTs主要对可见的切连科夫光子敏感。 使用来自$^{22}$钠源的伽马射线产生亚兆电子伏特电子，我们以$>5\sigma$的置信度隔离了即时切连科夫光，并开发了一种选择方法以获得低背景的电磁样本。 这是在高产率闪烁体探测器中首次对亚兆电子伏特电子的切连科夫光子进行逐事件观测，标志着低能粒子探测器发展的里程碑。 显示英文摘要

摘要： This Letter reports the event-by-event observation of Cherenkov light from sub-MeV electrons in a high scintillation light-yield liquid argon (LAr) detector by the Coherent CAPTAIN-Mills (CCM) experiment. The CCM200 detector, located at Los Alamos National Laboratory, instruments 7 tons (fiducial volume) of LAr with 200 8-inch photomultiplier tubes (PMTs), 80% of which are coated in a wavelength shifting material and the remaining 20% are uncoated. In the prompt time region of an event, defined as $-6 \leq t \leq 0$ ns relative to the event start time $t=0$, the uncoated PMTs are primarily sensitive to visible Cherenkov photons. Using gamma-rays from a $^{22}$Na source for production of sub-MeV electrons, we isolated prompt Cherenkov light with $>5\sigma$ confidence and developed a selection to obtain a low-background electromagnetic sample. This is the first event-by-event observation of Cherenkov photons from sub-MeV electrons in a high-yield scintillator detector, and represents a milestone in low-energy particle detector development.