One-loop Yukawa Couplings in Local Models

TL;DR

This paper calculates one-loop Yukawa couplings and threshold corrections in supersymmetric brane models at singularities, revealing both wavefunction and vertex corrections affecting the effective interactions.

Contribution

It provides a detailed computation of one-loop corrections, including a novel analysis of physical vertex corrections in the 1PI action for local string models.

Findings

Wavefunction renormalisation includes IR and UV contributions.

Threshold corrections depend on the Calabi-Yau volume.

Physical vertex corrections exist despite superpotential non-renormalisation.

Abstract

We calculate the one-loop Yukawa couplings and threshold corrections for supersymmetric local models of branes at singularities in type IIB string theory. We compute the corrections coming both from wavefunction and vertex renormalisation. The former comes in the IR from conventional field theory running and in the UV from threshold corrections that cause it to run from the winding scale associated to the full Calabi-Yau volume. The vertex correction is naively absent as it appears to correspond to superpotential renormalisation. However, we find that while the Wilsonian superpotential is not renormalised there is a physical vertex correction in the 1PI action associated to light particle loops.