Evidence for two neutrino mass eigenstates from SN 1987A and the possibility of superluminal neutrinos

This paper reports a new phenomenological analysis of the neutrino burst detected from SN 1987A, and it reveals the presence of two mass eigenstates. The heavier mass eigenstate has mH = 21.4 ± 1.2 eV/c2, while the lighter one has mL = 4.0 ± 0.5 eV/c2. It is not the first paper to make such a claim, but it expands on a 1988 conditional analysis by Cowsik, and it attempts to make the evidence more robust through an improved statistical analysis, and through providing reasons why alternative explanations are unlikely. It also shows how the result can be made consistent with existing smaller electron neutrino mass limits from tritium beta decay and cosmology through the existence of a third tachyonic (superluminal) mass eigenstate.