An Analysis of Cosmic Neutrinos: Flavor Composition at Source and Neutrino Mixing Parameters

TL;DR

This paper investigates how cosmic neutrino flavor ratios can be used to determine neutrino mixing parameters and tests the initial flavor composition assumptions at neutrino telescopes like ICECUBE.

Contribution

It provides a detailed analysis of uncertainties affecting the extraction of neutrino mixing parameters from cosmic neutrino flavor data.

Findings

Feasibility of deriving mixing parameters from flavor ratios.

Impact of initial flavor ratio deviations on measurements.

Uncertainty analysis for neutrino flavor composition at detectors.

Abstract

We examine the feasibility of deriving neutrino mixing parameters $\delta$ and $\theta_{13}$ from the cosmic neutrino flavor composition under the assumption that the flavor ratios of the cosmic neutrinos at the source were $F_{\nu_e}+F_{\bar{\nu}_e}:F_{\nu_\mu}+F_{\bar{\nu}_\mu}: F_{\nu_\tau}+F_{\bar{\nu}_\tau}=1:2:0$. We analyze various uncertainties that enter the derivation of $\delta$ and $\theta_{13}$ from the ratio of the shower-like to $\mu$-tracks events which is the only realistic source of information on the flavor composition at neutrino telescopes such as ICECUBE. We then examine to what extent the deviation of the initial flavor ratio from $1:2:0$ can be tested by measurement of this ratio at neutrino telescopes taking into account various sources of uncertainty.