Flavor Composition of UHE Neutrinos at Source and at Neutrino Telescopes

TL;DR

This paper explores how neutrino telescopes can determine the initial flavor composition of astrophysical neutrinos and identifies a neutrino mixing scenario with a constant muon neutrino ratio regardless of source composition.

Contribution

It introduces a simple parametrization of initial neutrino fluxes and analyzes a unique mixing scenario with fixed muon neutrino ratios independent of source details.

Findings

Neutrino telescopes can constrain the source flavor composition parameter n.

A specific neutrino mixing scenario yields a constant muon neutrino ratio.

Phenomenological implications of this mixing scenario are discussed.

Abstract

We parameterize the initial flux composition of high energy astrophysical neutrinos as (Phi_e^0 : Phi_mu^0 : Phi_tau^0) = (1 : n : 0), where n characterizes the source. All usually assumed neutrino sources appear as limits of this simple parametrization. We investigate how precise neutrino telescopes can pin down the value of n. We furthermore show that there is a neutrino mixing scenario in which the ratio of muon neutrinos to the other neutrinos takes a constant value regardless of the initial flux composition. This occurs when the muon neutrino survival probability takes its minimal allowed value. The phenomenological consequences of this very predictive neutrino mixing scenario are given.