Grand Unification and Exotic Fermions

TL;DR

This paper uses LieART software to demonstrate that certain SU(N) grand unified theories can produce only standard model fermions without light exotic fermions, aiding future model building.

Contribution

It introduces a method to construct GUT models with chiral fermions in mixed tensor representations that avoid light exotic fermions.

Findings

SU(N) GUTs can yield only standard model fermions

Tabulated results for model building are provided

An SU(6) toy model illustrates the approach

Abstract

We exploit the recently developed software package LieART to show that SU(N) grand unified theories with chiral fermions in mixed tensor irreducible representations can lead to standard model chiral fermions without additional light exotic chiral fermions, i.e., only standard model fermions are light in these models. Results are tabulated which may be of use to model builders in the future. An SU(6) toy model is given and model searches are discussed.