Large Mixing Angle MSW and Atmospheric Neutrinos from Single Right-Handed Neutrino Dominance and U(1) Family Symmetry

TL;DR

This paper explores how single right-handed neutrino dominance combined with a U(1) family symmetry can naturally produce large mixing angles in neutrino oscillations, explaining solar and atmospheric neutrino data.

Contribution

It demonstrates how large mixing angles compatible with the LMA MSW solution can emerge from SRHND with a U(1) symmetry, providing analytic conditions and systematic charge assignment analysis.

Findings

Large 12 mixing angles can be generated from SRHND.

Analytic conditions for SRHND are derived for one, two, and three right-handed neutrinos.

Systematic search for minimal U(1) charge models compatible with observed neutrino mixing.

Abstract

Single right-handed neutrino dominance (SRHND) in the 23 sector of the light effective neutrino mass matrix has been proposed as a natural explanation for the concurrent large 23 mixing angle and large 23 mass hierarchy. In this paper we show how large 12 mixing angles, suitable for the large mixing angle (LMA) MSW solution to the solar neutrino problem, may arise from SRHND. In order to understand the conditions for SRHND and LMA MSW we first consider the case of one and two right-handed neutrinos, and obtain simple analytic conditions which are then extended to the case of three right-handed neutrinos. We then introduce a single U(1) family symmetry and show how these analytic conditions may be translated into U(1) charge assignments and perform a systematic search for the simplest examples.