Earth matter effect on atmospheric neutrino oscillation in (3+3) model

TL;DR

This paper investigates how the (3+3) neutrino model, with three active and three sterile neutrinos, affects atmospheric neutrino oscillations through matter resonance effects in Earth, with implications for neutrino detection and hierarchy determination.

Contribution

It analyzes the impact of the (3+3) neutrino mixing scheme on atmospheric neutrino oscillations, highlighting matter resonance effects and potential experimental signatures in IceCube.

Findings

Matter resonance enhances oscillations inside Earth.

Maximal transitions occur at TeV energies.

Zenith angle distributions can probe neutrino hierarchy.

Abstract

In a recent combined analysis of short baseline neutrino oscillation data by Conrad et al it is shown that (3+3) neutrino model, defined by three active and three sterile neutrinos, results in an overall goodness of $67\%$ and a compatibility of $90\%$ among all data sets - to be compared to the compatibility of $0.043\% $ and $13\% $ for a (3+1) and a (3+2) model, respectively. Aside from the fact that (3+3) model still finds inconsistencies with MiniBooNE appearance data sets, its high quality overall compatibility and goodness of fit led us to study the atmospheric neutrinos in this model which travel distances of thousands of kilometers through earth. We show that in this mixing scheme matter resonance effect inside earth enhances the small vacuum oscillations into near-maximal transitions and at high energies these maximal transitions occur in the TeV range, whereas at low energies those can occur in the few GeV region. We also calculate the zenith angle distributions of $\nu_{\mu}^{CC}$(charged current) events in the 10 - 100 GeV energy range in DeepCore sub-array of the IceCube Neutrino Observatory and comment on the possibility of probing active neutrino mass hierarchy and six neutrino scenario.