Classifying and probing flavor transition mechanisms of astrophysical high energy neutrinos

Abstract

The future neutrino telescopes are expected to identify the flavors of astrophysical neutrinos and therefore determine the flavor ratio. The flavor ratio of astrophysical neutrinos observed at the Earth depends on both the initial flavor ratio at the source and flavor transitions taking place during the propagations of these neutrinos. We propose a model-independent way to parameterize the above flavor transitions, including standard oscillations and beyond. A systematical way is also described to probe those mechanisms taking advantage of R ≡ ϕμ/(ϕe + ϕτ) and S ≡ ϕe/eτ, the observables in neutrino telescope measurements.