GeV to TeV astrophysical tau neutrinos

Abstract Neutrinos with energy greater than GeV are copiously produced in the p ( A , p ) interactions occurring in several astrophysical sites such as (i) the Earth atmosphere, (ii) our galactic plane as well as in (iii) the galaxy clusters. A comparison of the tau and mu neutrino flux in the presence of neutrino oscillations from these three representative astrophysical sites is presented. It is pointed out that the non-atmospheric tau neutrino flux starts dominating over the downward going atmospheric tau neutrino flux for neutrino energy E as low as ∼ 10 GeV . This energy value is much lower than the energy value, E ⩾ 5 × 10 4 GeV , estimated for the dominance of the non-atmospheric mu neutrino flux, in the presence of neutrino oscillations. Future prospects for possible observations of non-atmospheric tau neutrino flux are briefly mentioned.