Predictions From High Scale Mixing Unification Hypothesis

TL;DR

This paper explores how the High Scale Mixing Unification hypothesis, combined with renormalization group evolution, predicts small leptonic mixing angles and non-maximal mixing, offering testable differences between Dirac and Majorana neutrinos.

Contribution

It introduces a framework linking high scale mixing unification with low scale neutrino parameters, including predictions for mixing angles and distinctions between neutrino types.

Findings

Predicts non-zero small $ heta_{13}$ from RG evolution

Finds $ heta_{23}$ is non-maximal in most parameter ranges

Provides constraints on SUSY breaking and unification scales

Abstract

Starting with 'High Scale Mixing Unification' hypothesis, we investigate the renormalization group evolution of mixing parameters and masses for both Dirac and Majorana type neutrinos. Following this hypothesis, the PMNS mixing parameters are taken to be identical to the CKM ones at a unifying high scale. Then, they are evolved to a low scale using MSSM renormalization-group equations. For both type of neutrinos, the renormalization group evolution 'naturally' results in a non-zero and small value of leptonic mixing angle $\theta_{13}$. One of the important predictions of this analysis is that, in both cases, the mixing angle $\theta_{23}$ turns out to be non-maximal for most of the parameter range. We also elaborate on the important differences between Dirac and Majorana neutrinos within our framework and how to experimentally distinguish between the two scenarios. Furthermore, for both cases, we also derive constraints on the allowed parameter range for the SUSY breaking and unification scales, for which this hypothesis works. The results can be tested by present and future experiments.