Study of the KL → π0 ν ν Decay at the J-PARC KOTO Experiment
Journal
Physical Review Letters
Journal Volume
126
Journal Issue
12
Date Issued
2021
Author(s)
Ahn J. K. et al. (KOTO Collaboration)
Abstract
The rare decay KL 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±0.05stat±0.66syst)×10-10, three candidate events were observed in the signal region. After unveiling them, contaminations from K± and scattered KL 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 KL→ π0ν ν at the 90% confidence level. ? 2021 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.
Subjects
Atomic physics; Branching fractions; Confidence levels; Rare decays; Single event; Upper limits; Physics; article; contamination; expectation
Type
journal article