Sensitivity of the Hyper-Kamiokande experiment to neutrino oscillation parameters using accelerator neutrinos

Journal article

This paper presents the expected sensitivity to the neutrino oscillation parameters of the Hyper-Kamiokande long-baseline program. The Hyper-Kamiokande experiment, currently under construction in Japan, will measure the oscillations of accelerator-produced neutrinos with thousands of selected events per sample: this corresponds to an increase of statistics of a factor 25–100 with respect to recent results from the currently-running long-baseline neutrino oscillation experiment in Japan, T2K. In the most favorable scenario we will achieve the discovery of Charge-Parity (CP) violation in neutrino oscillation at 5σ$$5\sigma $$ C.L. in less than 3 years. With 10 years of data-taking, and assuming a neutrino : antineutrino beam running ratio of 1:3, a CP violation discovery at 5σ$$5\sigma $$ C.L. is possible for more than 60% of the actual values of the CP-violating phase, δCP.$$\delta _{CP}.$$ Moreover, we will measure δCP$$\delta _{CP}$$ with a precision ranging from 20∘,$$^{\circ },$$ in the case of maximal CP violation, to 6∘,$$^{\circ },$$ in the case of CP conservation. We aim to achieve a 0.5% resolution on the Δm322$$\Delta m^2_{32}$$ parameter, and a resolution between 3% and 0.5% on the sin2θ23$$\sin ^2\theta _{23}$$ parameter, depending on its true value. These results are obtained by extending the analysis methods of T2K with dedicated tuning to take into account the Hyper-Kamiokande design: the larger far detector, the more powerful beam, the upgraded near detector ND280, and the planned additional Intermediate Water Cherenkov Detector.

Authors: Abe, K; Afif, MT; Laamara, RA; Aihara, H; Ajmi, A

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: SpringerOpen
• Journal: The European Physical Journal C
• Volume: 86
• Issue: 2
• Pages: 170
• Publication date: 2026-02-23
• DOI: 10.1140/epjc/s10052-025-14938-9
• EISSN: 1434-6052
• ISSN: 1434-6044
• Language: English
• Keywords: Solar neutrino; Neutrino oscillation; CP violation; Measurements of neutrino speed; Measure (data warehouse); Neutrino; Oscillation (cell signaling); Sensitivity (control systems)