Narrow Results

Neutrinos with energy greater than GeV are copiously produced in the p(A,p) interactions occurring in the earth atmosphere and in our galactic plane. A comparison of the tau and mu neutrino flux in the presence of neutrino oscillations from these two astrophysical sites is presented. It is pointed out that the galactic plane tau neutrino flux dominates over the downward going atmospheric tau neutrino flux at much lower energy value than that for the dominance of the mu neutrino flux from these two sites. Future prospects for possible observations of galactic tau neutrino flux are also briefly mentioned.

The pp interactions taking place in the cosmos around us are a source of the astrophysical neutrinos of all the three flavors. In these interactions, the electron and the muon neutrinos mainly come from the production and the decay of the π^± mesons, whereas the tau neutrinos mainly come from the production and the decay of the mesons. We estimate the three intrinsic neutrino flavor ratios for 1 GeV ≤E≤10¹² GeV in the pp interactions and found them to be 1:2:3×10^-5. We study the effects of neutrino oscillations on these intrinsic ratios. We point out that the three ratios become 1:1:1 if L(pc)/E(GeV)≥10^-10 in the presence of neutrino oscillations, where L is the distance to the astrophysical neutrino source in units of parsecs.