Inverted Hierarchy of Neutrino Masses Disfavored by Supernova 1987A
  We discuss the flavor conversion of supernova neutrinos in the three-flavor mixing scheme of neutrinos. We point out that by neutrino observation from supernova one can discriminate the inverted hierarchy of neutrino masses from the normal one if s_{13}^2 \gsim a few \times 10^{-4}, irrespective of which oscillation solution to the solar neutrino problem is realized in nature. We perform an analysis of data of SN1987A and obtain a strong indication that the inverted mass hierarchy is disfavored unless s_{13}^2 \lsim a few \times 10^{-4}. 
Hisakazu Minakata and Hiroshi Nunokawa