Effective Action of Matter Fields in Four-Dimensional String Orientifolds

TL;DR

This paper investigates the Kahler metric for matter fields in type IIB string theory orientifolds, revealing how it encodes anomalous dimensions and moduli dependence, with explicit calculations confirming supersymmetry predictions.

Contribution

It provides explicit calculations of the Kahler metric and disk amplitudes in N=1,2 orientifold compactifications, connecting string theory results with field theory anomalous dimensions.

Findings

Infrared-divergent part reproduces anomalous dimensions.

Moduli-dependent part arises from N=2 sectors.

Couplings align with supersymmetry expectations.

Abstract

We study various aspects of the Kahler metric for matter fields in N=1,2 orientifold compactifications of type IIB string theory. The result has an infrared-divergent part which reproduces the field- theoretical anomalous dimensions, and a moduli-dependent part which comes from N=2 sectors of the orientifold. For the N=2 orientifolds, we also compute the disk amplitude for two matter fields on the boundary and a twisted closed string modulus in the bulk. Our results are in agreement with supersymmetry: the singlet under the SU(2)_R R-symmetry has vanishing coupling, while the coupling of the SU(2)_R triplet does not vanish.