在日本质子加速器研究中心（J-PARC）的KOTO实验中对\(K_{L}→π^{0}νν\)衰变的研究。

Study of the K_{L}→π^{0}νν[over ¯] Decay at the J-PARC KOTO Experiment.

作者信息

Ahn J K, Beckford B, Campbell M, Chen S H, Comfort J, Dona K, Farrington M S, Hanai K, Hara N, Haraguchi H, Hsiung Y B, Hutcheson M, Inagaki T, Isoe M, Kamiji I, Kato T, Kim E J, Kim J L, Kim H M, Komatsubara T K, Kotera K, Lee S K, Lee J W, Lim G Y, Lin Q S, Lin C, Luo Y, Mari T, Masuda T, Matsumura T, Mcfarland D, McNeal N, Miyazaki K, Murayama R, Nakagiri K, Nanjo H, Nishimiya H, Noichi Y, Nomura T, Nunes T, Ohsugi M, Okuno H, Redeker J C, Sanchez J, Sasaki M, Sasao N, Sato T, Sato K, Sato Y, Shimizu N, Shimogawa T, Shinkawa T, Shinohara S, Shiomi K, Shiraishi R, Su S, Sugiyama Y, Suzuki S, Tajima Y, Taylor M, Tecchio M, Togawa M, Toyoda T, Tung Y-C, Vuong Q H, Wah Y W, Watanabe H, Yamanaka T, Yoshida H Y, Zaidenberg L

机构信息

Department of Physics, Korea University, Seoul 02841, Republic of Korea.

Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA.

出版信息

Phys Rev Lett. 2021 Mar 26;126(12):121801. doi: 10.1103/PhysRevLett.126.121801.

DOI:10.1103/PhysRevLett.126.121801

PMID:33834796

Abstract

The rare decay K_{L}→π^{0}νν[over ¯] 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±0.05_{stat}±0.66_{syst})×10^{-10}, three candidate events were observed in the signal region. After unveiling them, contaminations from K^{±} and scattered K_{L} decays were studied, and the total number of background events was estimated to be 1.22±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 4.9×10^{-9} on the branching fraction of K_{L}→π^{0}νν[over ¯] at the 90% confidence level.

摘要

利用2016年、2017年和2018年在日本质子加速器研究中心（J-PARC）的KOTO实验中采集的数据集，对罕见衰变(K_{L}→π^{0}νν\overline{})进行了研究。单事例灵敏度为((7.20±0.05_{统计}±0.66_{系统})×10^{-10})，在信号区域观察到三个候选事例。在揭示这些事例后，研究了来自(K^{±})和散射(K_{L})衰变的本底，估计本底事例总数为(1.22±0.26)。我们得出结论，观察到的事例数在统计上与本底预期一致。对于该数据集，我们在90%置信水平下对(K_{L}→π^{0}νν\overline{})的分支比设定了(4.9×10^{-9})的上限。