Fermion Mass Hierarchy and Mixing in simplified Grand Gauge-Higgs Unification

TL;DR

This paper explores a five-dimensional SU(6) gauge theory model that unifies gauge and Higgs fields, aiming to explain the fermion mass hierarchy and mixing in the Standard Model through boundary and bulk fermions with localized gauge kinetic terms.

Contribution

It presents a simplified SU(6) gauge theory model with fewer bulk fermions that successfully reproduces fermion mass hierarchy and mixing, improving upon previous models.

Findings

Reproduces SM fermion mass hierarchy and mixing

Reduces the number of bulk fermions needed

Achieves results with mild parameter tuning

Abstract

Grand gauge-Higgs unification of five dimensional SU(6) gauge theory on an orbifold $S^1 / Z_2$ with localized gauge kinetic terms is discussed. The Standard model (SM) fermions on the boundaries and some massive bulk fermions coupling to the SM fermions are introduced. The number of the bulk fermions is reduced compared to the previous model, which reproduces the generation mixing of the SM fermions in addition to the SM fermion mass hierarchy by mild tuning the bulk masses and parameters of the localized gauge kinetic terms.