Ambiguity in source flux of high - energy cosmic neutrinos ⋆

For high energy cosmic neutrinos Athar, Jeźabek, and Yasuda (AJY) have recently shown that the existing data on neutrino oscillations suggests that cosmic neutrino flux at the AGN/GRB source, F (νe) : F (νμ) : F (ντ ) ≈ 1 : 2 : 0, oscillates to F (νe) : F (νμ) : F (ντ ) ≈ 1 : 1 : 1. These results can be confirmed at AMANDA, Baikal, ANTARES and NESTOR, and other neutrino detectors with a good flavor resolution. Here, we re-derive the AJY result from quasi bimaximal mixing, and show that observation of F (νe) : F (νμ) : F (ντ ) ≈ 1 : 1 : 1 does not necessarily establish cosmic neutrino flux at the AGN/GRB source to be F (νe) : F (νμ) : F (ντ ) ≈ 1 : 2 : 0.