Q_6 flavor symmetry model for the extension of the minimal standard model by three right-handed sterile neutrinos

TL;DR

This paper proposes a Q_6 flavor symmetry model extending the minimal standard model with three sterile neutrinos, explaining neutrino mass hierarchies, mixing angles, and active-sterile mixing naturally.

Contribution

It introduces a novel Q_6 flavor symmetry framework that naturally explains sterile neutrino masses, mixing angles, and the neutrino mass hierarchy.

Findings

Predicts a normal hierarchical neutrino mass spectrum.

Achieves nonzero theta_{13} consistent with experimental data.

Links active-sterile mixing to neutrino mass ratios.

Abstract

The extension of the minimal standard model by three right-handed sterile neutrinos with masses smaller than the electroweak scale (nuMSM) is discussed in a Q_6 flavor symmetry framework. The lightness of the keV sterile neutrino and the near mass degeneracy of two heavier sterile neutrinos are naturally explained by exploiting group properties of Q_6. A normal hierarchical mass spectrum and an approximately mu-tau symmetric mass matrix are predicted for three active neutrinos. Nonzero theta_{13} can be obtained together with a deviation of theta_{23} from the maximality, where both mixing angles are consistent with the latest global data including T2K and MINOS results. Furthermore, the tiny active-sterile mixing is related to the mass ratio between the lightest active and lightest sterile neutrinos.