Two-Point Functions of Chiral Fields at One Loop in Type II

TL;DR

The authors address the one-loop corrections to the Kähler metric of chiral matter in toroidal Type II orientifolds with D6-branes, focusing on both branes at orbifold fixed points and branes intersecting at angles. They develop and apply boundary-changing operator techniques to compute annulus and Möbius-strip amplitudes, with worldsheet instanton effects encoded by classical actions on the string worldsheet. The main results are a moduli-dependent, worldsheet-instanton–driven contribution for intersecting branes and a universal, moduli-independent piece for N=1 sectors, together with a field-theory limit that reproduces the expected anomalous dimensions and Yukawa-induced thresholds. The work provides a comprehensive framework to extract one-loop Kähler metrics and threshold corrections, enabling applications to Yukawa couplings, SUSY breaking mediation, and precise coupling unification in string compactifications.

Abstract

We compute the two-point functions for chiral matter states in toroidal intersecting D6-brane models. In particular, we provide the techniques to calculate Moebius strip diagrams including the worldsheet instanton contribution.

Figures (2)

• Figure 1: Canonical dissection of torus.
• Figure 2: Canonical dissection of doubled Möbius strip.