FRACTIONAL BRANES, CONFINEMENT, AND DYNAMICALLY GENERATED SUPERPOTENTIALS

We examine the effects of instantons in four-dimensional N = 1 supersy mmetric gauge theory by including D0-branes in type IIA brane construc tions, We examine instanton-generated superpotentials in supersymmetri c QCD and find that they are due to a repulsive force between D4-brane s bound to D0-branes ending on NS 5-branes. We study situations where instanton effects break supersymmetry such as the Intriligator-Thomas- Izawa-Yangagida model and relate this to a IIA brane construction. We also argue how confinement due to a condensate of fractional instanton s manifests itself in super Yang-Mills theory using fractional D0-bran es, D4-branes, and NS-strings. (C) 1998 Published by Elsevier Science B.V.