Neutrino mixing scenarios and AGN

TL;DR

This paper explores how neutrinos from active galactic nuclei can be used to test various neutrino mixing models, including sterile neutrino scenarios, by analyzing their flavor composition.

Contribution

It derives the expected flavor composition of AGN neutrinos under different mixing schemes and demonstrates how these observations can distinguish between models, especially testing sterile neutrinos.

Findings

Most mixing schemes can be distinguished using AGN neutrino data

Sterile neutrino existence can be specifically tested

AGN neutrinos can probe four-neutrino oscillation scenarios

Abstract

Active galactic nuclei (AGN) have been suggested to be sources of very high energy neutrinos. We consider the possibility of using AGN neutrinos to test neutrino mixings. From the atmospheric, solar and laboratory data on neutrino oscillations we derive the flavour composition of the AGN neutrino flux in different neutrino mixing schemes. We show that most of the schemes considered can be distinguished from each other and the existence of a sterile neutrino can be specially tested. AGN neutrinos can also be used to test those four-neutrino scenarios where solar neutrinos oscillate into an arbitrary mixture of $\nu_s$ and $\nu_\tau$.