Non-perturbative Yukawa Couplings from String Instantons

TL;DR

This paper explores how non-perturbative D-brane instantons in string theory can generate important Yukawa couplings and mass terms that are absent at the perturbative level, impacting model building in string phenomenology.

Contribution

It demonstrates the generation of perturbatively forbidden Yukawa couplings and matter mass terms via D-brane instantons in a specific string compactification model.

Findings

Generation of the SU(5) GUT Yukawa coupling 10 10 5_H

Mass terms for matter fields in a D6-brane model

Mechanism for decoupling exotic matter

Abstract

Non-perturbative D-brane instantons can generate perturbatively absent though phenomenologically relevant couplings for Type II orientifold compactifications with D-branes. We discuss the generation of the perturbatively vanishing SU(5) GUT Yukawa coupling of type 10 10 5_H. Moreover, for a simple globally consistent intersecting D6-brane model, we discuss the generation of mass terms for matter fields. This can serve as a mechanism for decoupling exotic matter.