Relating quarks and leptons without grand-unification

TL;DR

This paper presents a model combining supersymmetry and flavor symmetry to relate quark and lepton properties without grand-unification, successfully explaining fermion mass hierarchies and predicting specific correlations.

Contribution

It introduces an SU(3)xSU(2)xU(1) model with A4 flavor symmetry that reproduces fermion hierarchies and predicts novel relations between quark and lepton mixing angles.

Findings

Relation between down-type quark and charged lepton masses

Correlation between Cabibbo angle and reactor angle in neutrino oscillations

Reproduces observed fermion mass hierarchies

Abstract

In combination with supersymmetry, flavor symmetry may relate quarks with leptons, even in the absence of a grand-unification group. We propose an SU(3)xSU(2)xU(1) model where both supersymmetry and the assumed A4 flavor symmetries are softly broken, reproducing well the observed fermion mass hierarchies and predicting: (i) a relation between down-type quarks and charged lepton masses, and (ii) a correlation between the Cabibbo angle in the quark sector, and the reactor angle characterizing CP violation in neutrino oscillations.