Finite Theories and Marginal Operators on the Brane

Abstract

We show how to use D and NS fivebranes in Type IIB superstring theory to construct large classes of finite N=1 supersymmetric four dimensional field theories. In this construction, the beta functions of the theories are directly related to the bending of branes; in finite theories the branes are not bent, and vice versa. Many of these theories have multiple dimensionless couplings. A group of duality transformations acts on the space of dimensionless couplings; for a large subclass of models, this group always includes an overall SL(2,\ZZ) invariance. In addition, we find even larger classes of theories which, although not finite, also have one or more marginal operators.Comment: 32 pages, 13 figures, uses revte