Instantons and Holomorphic Couplings in Intersecting D-brane Models

TL;DR

This paper investigates string D-instanton calculus in intersecting D-brane models, deriving constraints on moduli dependence, computing one-loop corrections, and analyzing instanton effects on superpotential and gauge kinetic functions.

Contribution

It extends the D-instanton calculus framework, relates one-loop determinants to threshold corrections, and explores instanton effects on superpotential and gauge kinetic functions.

Findings

One-loop determinants relate to open string threshold corrections.

Fayet-Iliopoulos terms are proportional to gauge threshold corrections.

Constraints on moduli dependence of matter field Kähler potentials.

Abstract

We clarify certain aspects and discuss extensions of the recently introduced string D-instanton calculus (hep-th/0609191). The one-loop determinants are related to one-loop open string threshold corrections in intersecting D6-brane models. Utilising a non-renormalisation theorem for the holomorphic Wilsonian gauge kinetic functions, we derive a number of constraints for the moduli dependence of the matter field Kaehler potentials of intersecting D6-brane models on the torus. Moreover, we compute string one-loop corrections to the Fayet-Iliopoulos terms on the D6-branes finding that they are proportional to the gauge threshold corrections. Employing these results, we discuss the issue of holomorphy for E2-instanton corrections to the superpotential. Eventually, we discuss E2-instanton corrections to the gauge kinetic functions and the FI-terms.