SO(32) heterotic line bundle models

TL;DR

This paper constructs three-generation standard-like models from $SO(32)$ heterotic string theory using line bundles on Calabi-Yau threefolds, revealing realistic gauge groups and particle spectra with implications for proton decay.

Contribution

It introduces a method to derive realistic particle physics models from $SO(32)$ heterotic string theory with specific line bundle configurations, connecting to intersecting D-brane models.

Findings

Realistic gauge groups with three generations of quarks and leptons.

Presence of vector-like particles and extra $U(1)_{B-L}$ symmetry.

Control of Yukawa couplings and proton decay operators by anomalous U(1) symmetries.

Abstract

We search for the three-generation standard-like and/or Pati-Salam models from the $SO(32)$ heterotic string theory on smooth, quotient complete intersection Calabi-Yau threefolds with multiple line bundles, each with structure group $U(1)$. These models are S- and T-dual to intersecting D-brane models in type IIA string theory. We find that the stable line bundles and Wilson lines lead to the standard model gauge group with an extra $U(1)_{B-L}$ via a Pati-Salam-like symmetry and the obtained spectrum consists of three chiral generations of quarks and leptons, and vector-like particles. Green-Schwarz anomalous U(1) symmetries control not only the Yukawa couplings of the quarks and leptons but also the higher-dimensional operators causing the proton decay.