Large lepton mixing and SN 1987A

We reconsider the impact of ν-bare↔ν-barμ,τ neutrino oscillations on the observed ν-bare signal of supernova SN 1987A. Performing a maximum-likelihood analysis using as fit parameters the released binding energy Eb and the average neutrino energy , we find as previous analyzes that ν-bare↔ν-barμ,τ oscillations with large mixing angles have lower best-fit values for than small-mixing angle (SMA) oscillations, which already turn out to be smaller than those found in simulations. In order to quantify the degree to which the experimental data favor the SMA over the large mixing solutions we use their likelihood ratios as well as a Kolmogorov-Smirnov test. We find within the range of SN parameters predicted by simulations regions in which the LMA-MSW solution is either only marginally disfavored or favored compared to the SMA-MSW solution. We conclude therefore that the LMA-MSW solution is not in conflict with the current understanding of SN physics. In contrast, the vacuum oscillation and the LOW solutions to the solar neutrino problem can be excluded at the 4σ level for most of the SN parameter ranges found in simulations