CP Violation and Neutrino Masses and Mixings from Quark Mass Hierarchies

TL;DR

This paper explores how quark mass hierarchies influence neutrino masses, mixings, and CP violation within a six-dimensional supersymmetric SO(10) GUT model, revealing natural explanations for observed neutrino properties.

Contribution

It introduces a novel six-dimensional orbifold SO(10) GUT framework linking quark and lepton mass matrices and CP phases, explaining neutrino mass hierarchy and mixing patterns.

Findings

Quark mass hierarchies determine CKM matrix and lepton masses.

Neutrino mass hierarchy arises from up-down quark hierarchy mismatch.

Model accommodates large atmospheric mixing and small reactor angle.

Abstract

We study the connection between quark and lepton mass matrices in a supersymmetric SO(10) GUT model in six dimensions, compactified on an orbifold. The physical quarks and leptons are mixtures of brane and bulk states. This leads to a characteristic pattern of mass matrices and high-energy CP violating phases. The hierarchy of up and down quark masses determines the CKM matrix and most charged lepton and neutrino masses and mixings. The small hierarchy of neutrino masses is a consequence of the mismatch of the up and down quark mass hierarchies. The effective CP violating phases in the quark sector, neutrino oscillations and leptogenesis are unrelated. In the neutrino sector we can accomodate naturally $\sin \theta_{23} \sim 1$, $\sin \theta_{13} \lesssim 0.1$ and $m_1 \lesssim m_2 \sim \sqrt{\Delta m^2_\text{sol}} < m_3 \sim \sqrt{\Delta m^2_\text{atm}}$.