Pseudo-Dirac Neutrino Scenario: Cosmic Neutrinos at Neutrino Telescopes

TL;DR

This paper explores how cosmic neutrino observations at telescopes like IceCube can test the pseudo-Dirac neutrino scenario involving sterile neutrinos with tiny mass differences, affecting flavor ratios of arriving neutrinos.

Contribution

It analyzes the potential of neutrino telescopes to detect sterile neutrinos in the pseudo-Dirac scenario through flavor ratio measurements, considering uncertainties and source variations.

Findings

Neutrino telescopes can probe tiny mass squared differences in the pseudo-Dirac scenario.

Flavor ratio measurements can discriminate between pseudo-Dirac and standard neutrino models.

Results are robust against initial flavor ratio uncertainties.

Abstract

Within the "pseudo-Dirac" scenario for massive neutrinos the existence of sterile neutrinos which are almost degenerate in mass with the active ones is hypothesized. The presence of these sterile neutrinos can affect the flavor composition of cosmic neutrinos arriving at Earth after traveling large distances from astrophysical objects. We examine the prospects of neutrino telescopes such as IceCube to probe the very tiny mass squared differences 10^(-12) eV^2<\Delta m^2<10^(-19) eV^2, by analyzing the ratio of $\mu$-track events to shower-like events. Considering various sources of uncertainties which enter this analysis, we examine the capability of neutrino telescopes to verify the validity of the pseudo-Dirac neutrino scenario and especially to discriminate it from the conventional scenario with no sterile neutrino. We also discuss the robustness of our results with respect to the uncertainties in the initial flavor ratio of neutrinos at the source.