Gauged Flavor, Supersymmetry and Grand Unification

TL;DR

This paper reviews a model where flavor symmetry breaking explains all fermion masses and couplings, involving heavy vector-like fermions, and explores extensions to supersymmetry and grand unification.

Contribution

It introduces a gauged flavor model with left-right symmetry that links flavor breaking to fermion masses and proposes a grand unified framework based on $SU(5)_L\times SU(5)_R$.

Findings

Heavy vector-like fermions transmit flavor symmetry breaking to quarks and leptons.

Extension to supersymmetry is discussed, with implications for flavor physics.

A speculative grand unified model based on $SU(5)_L\times SU(5)_R$ is proposed.

Abstract

I review a recent work on gauged flavor with left-right symmetry, where all masses and all Yukawa couplings owe their origin to spontaneous flavor symmetry breaking. This is suggested as a precursor to a full understanding of flavor of quarks and leptons. An essential ingredient of this approach is the existence of heavy vector-like fermions, which is the home of flavor, which subsequently gets transmitted to the familiar quarks and leptons via the seesaw mechanism. I then discuss implications of extending this idea to include supersymmetry and finally speculate on a possible grand unified model based on the gauge group $SU(5)_L\times SU(5)_R$ which provides a group theoretic origin for the vector-like fermions.