Quark-Lepton Mass Relation in a Realistic A4 Extension of the Standard Model

TL;DR

This paper introduces a realistic A4 flavor symmetry extension of the Standard Model that explains quark-lepton mass relations, neutrino mixing, and CP violation without requiring grand unification or supersymmetry.

Contribution

It presents a novel A4-based model that reproduces observed fermion masses, mixing angles, and CP violation, and proposes a new neutrino mass matrix pattern compatible with experimental data.

Findings

Reproduces quark and lepton mass ratios accurately

Achieves acceptable neutrino mixing angles, including reactor angle

Provides a numerical fit for quark masses, mixing, and CP violation

Abstract

We propose a realistic A4 extension of the Standard Model involving a particular quark-lepton mass relation, namely that the ratio of the third family mass to the geometric mean of the first and second family masses are equal for down-type quarks and charged leptons. This relation, which is approximately renormalization group invariant, is usually regarded as arising from the Georgi-Jarlskog relations, but in the present model there is no unification group or supersymmetry. In the neutrino sector we propose a simple modification of the so called Zee-Wolfenstein mass matrix pattern which allows an acceptable reactor angle along with a deviation of the atmospheric and solar angles from their bi-maximal values. Quark masses, mixing angles and CP violation are well described by a numerical fit.