title: Nonperturbative yukawa couplings from string instantons.
abstract: Nonperturbative D-brane instantons can generate perturbatively absent though phenomenologically relevant couplings for type II orientifold compactifications with D-branes. We discuss the generation of the perturbatively vanishing SU(5) GUT Yukawa coupling of type <10 10 5(H)>. Moreover, for a simple globally consistent intersecting D6-brane model, we discuss the generation of mass terms for matter fields. This can serve as a mechanism for decoupling exotic matter.
authors: Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München, Germany.
authors: Ralph
authors: R
authors: Blumenhagen
authors: Mirjam
authors: M
authors: Cvetic
authors: Dieter
authors: D
authors: Lüst
authors: Robert
authors: R
authors: Richter
authors: Timo
authors: T
authors: Weigand