The "landscape" of Pati--Salam heterotic superstring vacua

TL;DR

This paper introduces a classification method for a vast landscape of heterotic superstring vacua, focusing on Pati--Salam models, and identifies a subset free of fractionally charged states, advancing string phenomenology.

Contribution

It develops a new classification technique for heterotic string vacua and identifies a significant subset with desirable phenomenological properties.

Findings

Classified approximately 10^15 heterotic vacua based on phenomenological features.

Identified about one million vacua with spectra free of fractionally charged states.

Provided insights into the distribution of vacua with realistic gauge symmetries.

Abstract

The main aspects of a recently developed method for classification of heterotic superstring vacua in the Free Fermionic Formulation are presented. Using these techniques we classify a big number of approximately $10^{15}$ heterotic string vacua with Pati--Salam, SU(4)x{SU(2)}_Lx{SU(2)}_R gauge symmetry with respect to their main phenomenological features as the number of families, Pati--Salam breaking Higgs, Standard Model Higgs doublets, additional triplets and exotic charge states. We identify an interesting subclass of these vacua, approximately one to one million, whose massless spectrum is completely free of fractionally charge states.