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Study of the $K_L \!\to\! \pi^0 \nu \overline{\nu}$ Decay at the J-PARC KOTO Experiment
- Source :
- Phys. Rev. Lett. 126, 121801 (2021)
- Publication Year :
- 2020
-
Abstract
- The rare decay $K_L \!\to\! \pi^0 \nu \overline{\nu}$ 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 $K_L \!\to\! \pi^0 \nu \overline{\nu}$ at the 90% confidence level.<br />Comment: 6 pages, 5 figures; published version, no change in the results. Fig. 2 and Fig. 4 were revised. In Fig. 5, the plot of the $P_{t}$ versus ${Z_{\mathrm{vtx}}}$ of the beam-halo $K_L\!\to\!2\gamma$ background events was added as Fig. 5 (b)
- Subjects :
- High Energy Physics - Experiment
Subjects
Details
- Database :
- arXiv
- Journal :
- Phys. Rev. Lett. 126, 121801 (2021)
- Publication Type :
- Report
- Accession number :
- edsarx.2012.07571
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1103/PhysRevLett.126.121801