Classification of Standard Model Particles in $E_6$ Orbifold Grand Unified Theories

TL;DR

This paper classifies Standard Model fermions arising from bulk fields in $E_6$ orbifold GUTs, focusing on zero modes of specific particles in higher-dimensional models.

Contribution

It provides a systematic classification of fermion zero modes in $E_6$ orbifold GUTs with specific surviving particles.

Findings

Identifies conditions for zero modes of $q$, $e^c$, and $u^c$

Classifies fermion representations in 5D and 6D models

Clarifies the origin of Standard Model fermions in orbifold GUTs

Abstract

We classify the standard model fermions, which originate from bulk fields of the $\bf{27}$ or $\bar{\bf{27}}$ representation after orbifold breaking, in $E_6$ grand unified theories on 5 or 6-dimensional space-time, under the condition that $q$, $e^c$ and $u^c$ survive as zero modes.