Real and complex random neutrino mass matrices and theta13

TL;DR

This paper demonstrates that small but non-zero theta13 neutrino mixing angles can be naturally produced by random models of neutrino mass matrices, with a preference for models including sterile neutrinos based on current data.

Contribution

It introduces a statistical analysis of real and complex neutrino mass matrices, including sterile neutrinos, showing their effectiveness in reproducing small theta13 values.

Findings

Random models can naturally produce small theta13 angles.

Complex matrices show qualitative differences from real matrices.

Data favors models with sterile neutrinos.

Abstract

Recently it has been shown that one of the basic parameters of the neutrino sector, so called theta13 angle is very small, but quite probably non-zero. We argue that the small value of theta13 can still be reproduced easily by a wide spectrum of randomly generated models of neutrino masses. For that we consider real and complex neutrino mass matrices, also including sterile neutrinos. A qualitative difference between results for real and complex mass matrices in the region of small theta13 values is observed. We show that statistically the present experimental data prefers random models of neutrino masses with sterile neutrinos.