An analysis of the Mikheyev-Smirnov-Wolfenstein effect using 1040 days of Kamiokande-II data is reported, which provides constraints on neutrino-oscillation parameters. The measured recoil-electron energy spectrum alone leads to the conclusion that the adiabatic region, 7.2×${10}^{\mathrm{-}4}$<${\sin }^2$2θ<6.3×${10}^{\mathrm{-}3}$, Δ${\mathit{m}}^2$∼1.3×${10}^{\mathrm{-}4}$ (eV${)}^2$, is disfavored at the 90% confidence level.

• Received 22 June 1990

DOI:https://doi.org/10.1103/PhysRevLett.65.1301