论文标题
研究$ k_l \！\ to \！在J-Parc Koto实验中π^0ν\覆盖$衰减
Study of the $K_L \!\to\! π^0 ν\overlineν$ Decay at the J-PARC KOTO Experiment
论文作者
论文摘要
稀有的衰减$ k_l \！\ to \！ π^0 ν\overlineν$ was studied with the dataset taken at the J-PARC KOTO experiment in 2016, 2017, and 2018. With a single event sensitivity of $( 7.20 \pm 0.05_{\rm stat} \pm 0.66_{\rm syst} ) \times 10^{-10}$, three candidate events were observed in the signal region.揭开它们后，研究了$ k^{\ pm} $的污染，并研究了零星的$ k_l $衰减，估计背景事件的总数为$ 1.22 \ pm 0.26 $。我们得出的结论是，观察到的事件的数量在统计上与背景期望一致。对于此数据集，我们将$ k_l \！\的分支分数上的上限设置为$ 4.9 \ times 10^{ - 9} $至\！在90％的置信度下，π^0ν\覆盖。
The rare decay $K_L \!\to\! π^0 ν\overlineν$ was studied with the dataset taken at the J-PARC KOTO experiment in 2016, 2017, and 2018. With a single event sensitivity of $( 7.20 \pm 0.05_{\rm stat} \pm 0.66_{\rm syst} ) \times 10^{-10}$, three candidate events were observed in the signal region. After unveiling them, contaminations from $K^{\pm}$ and scattered $K_L$ decays were studied, and the total number of background events was estimated to be $1.22 \pm 0.26$. We conclude that the number of observed events is statistically consistent with the background expectation. For this dataset, we set an upper limit of $4.9 \times 10^{-9}$ on the branching fraction of $K_L \!\to\! π^0 ν\overlineν$ at the 90% confidence level.
