We report a search for time variations of the solar 8 B neutrino flux using 5,804 live days of Super-Kamiokande data collected between May 31, 1996, and May 30, 2018. Super-Kamiokande measured the precise time of each solar neutrino interaction over 22 calendar years to search for solar neutrino flux modulations with unprecedented precision. Periodic modulations are searched for in a data set comprised of five-day interval solar neutrino flux measurements with a maximum likelihood method. We also applied the Lomb-Scargle method to this data set to compare it with previous reports. The only significant modulation found is due to the elliptic orbit of the Earth around the Sun. The observed modulation is consistent with astronomical data: we measured an eccentricity of (1.53±0.35) %, and a perihelion shift is (−1.5±13.5) days.

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An analysis of atmospheric neutrino data from all four run periods of Super-Kamiokande optimized for sensitivity to the neutrino mass hierarchy is presented. Confidence intervals for Δm 2 32 , sin 2 θ 23 , sin 2 θ 13 and δ CP are presented for normal neutrino mass hierarchy and inverted neutrino mass hierarchy hypotheses, based on atmospheric neutrino data alone. Additional constraints from reactor data on θ 13 and from published binned T2K data on muon neutrino disappearance and electron neutrino appearance are added to the atmospheric neutrino fit to give enhanced constraints on the above parameters. Over the range of parameters allowed at 90% confidence level, the normal mass hierarchy is favored by between 91.9% and 94.5% based on the combined Super-Kamiokande plus T2K result.

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We present limits on sterile neutrino mixing using 4,438 live-days of atmospheric neutrino data from the Super-Kamiokande experiment. We search for fast oscillations driven by an eV 2 -scale mass splitting and for oscillations into sterile neutrinos instead of tau neutrinos at the atmospheric mass splitting. When performing both of these searches we assume that the sterile mass splitting is large, allowing sin 2 ðΔm 2 L=4EÞ to be approximated as 0.5, and we assume that there is no mixing between electron neutrinos and sterile neutrinos (jU e4 j 2 ¼ 0). No evidence of sterile oscillations is seen and we limit jU μ4 j 2 to less than 0.041 and jU τ4 j 2 to less than 0.18 for Δm 2 > 0.1 eV 2 at the 90% C.L. in a 3 þ 1 framework. The approximations that can be made with atmospheric neutrinos allow these limits to be easily applied to 3 þ N models, and we provide our results in a generic format to allow comparisons with other sterile neutrino models.