Effective action of matter fields in four-dimensional string orientifolds

We study various aspects of the Kähler metric for matter fields in Script 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 Script N = 2 sectors of the orientifold. For the Script 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.