We study the rare decay K L →π 0 ν ##IMG## [https://ej.iop.org/icons/Entities/barnu.gif] {bar nu} at the J-PARC KOTO experiment. This decay mode is highly suppressed in the Standard Model (SM). The signature of the decay is two gammas from a π 0 decay and no other detectable particles. In the KOTO experiment, the two gammas are measured with a calorimeter which is composed of undoped cesium iodide (CsI) crystals. Each crystal is read out with a photomultiplier tube (PMT) attached on its rear side. One of the main backgrounds to K L →π 0 ν ##IMG## [https://ej.iop.org/icons/Entities/barnu.gif] {bar nu} is caused by neutrons in the beam halo. To reach the sensitivity predicted in the SM, we need to suppress the background further by a factor of ten. We dev...

中文翻译：

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四维量热仪，用于区分KOTO实验中子与中子的伽马

我们在J-PARC KOTO实验中研究了稀有衰变KL→π0ν## IMG ## [https://ej.iop.org/icons/Entities/barnu.gif] {bar nu}。在标准模型（SM）中，此衰减模式得到了高度抑制。衰减的特征是来自π0衰减的两个伽马，没有其他可检测到的粒子。在KOTO实验中，使用由未掺杂的碘化铯（CsI）晶体组成的量热计测量了两个伽马。读出每个晶体，并在其背面安装一个光电倍增管（PMT）。KL→π0ν## IMG ## [https://ej.iop.org/icons/Entities/barnu.gif] {bar nu}的主要背景之一是由束晕中的中子引起的。为了达到SM中预测的灵敏度，我们需要将背景进一步抑制十倍。我们开发...