Implications of Super-Kamiokande atmospheric low-energy data for solar neutrino oscillations

TL;DR

Super-Kamiokande's low-energy atmospheric neutrino data challenges the high-Delta m^2 large mixing angle MSW solution for solar neutrino oscillations, providing quantitative bounds within a three-neutrino framework.

Contribution

The paper demonstrates that low-energy atmospheric neutrino data constrains the high-Delta m^2 region of the solar neutrino oscillation parameter space, especially under the assumption of a small U_{e3} element.

Findings

High-Delta m^2 large mixing angle MSW solution is disfavored by data.

Quantitative bounds are established for three-neutrino oscillation parameters.

Results support a small U_{e3} element consistent with CHOOZ experiment.

Abstract

It is shown that the high-Delta m^2 part of the large mixing angle MSW solution of the solar neutrino problem is disfavored by the Super-Kamiokande data for low-energy upward-going events. A quantitative bound is obtained in the three-neutrino scheme with a negligibly small element U_{e3} of the neutrino mixing matrix, as indicated by the result of the CHOOZ long-baseline antinu_e->antinu_e oscillation experiment.