Neutrino telescopes as a probe of active and sterile neutrino mixings

If the ultrahigh-energy (UHE) neutrino fluxes produced from a distant astrophysical source can be measured at a km3-size neutrino telescope, they will provide a promising way to help determine the flavor mixing pattern of three active neutrinos. Considering the conventional UHE neutrino source with the flavor ratio ϕe:ϕμ:ϕτ=1:2:0, I show that holds at the detector of a neutrino telescope, where Δ characterizes the effect of μ-τ symmetry breaking (i.e., θ13≠0 and θ23≠π/4). Current experimental data yield −0.1⩽Δ⩽+0.1. It is also possible to probe Δ by detecting the flux of via the Glashow resonance channel anything. Finally, I give some brief comments on the possibility to constrain the mixing between active and sterile neutrinos by using the UHE neutrino telescopes.