Supersymmetry Breaking and Weakly vs. Strongly Coupled String Theory * Disclaimer

In the context of the field theory limit of superstrings, we consider an almost realistic model of supersymmetry breaking by gaugino condensation which includes, through nonperturbative corrections to the Kähler potential, dilaton stabilization at a value compatible with a weak coupling regime. Invariance under modular transformations is ensured through a Green-Schwarz term and string threshold corrections, which lead to moduli stabilization at the self-dual point. We are thus in a position to discuss several issues of physical relevance: gravitino, dilaton and moduli masses, axion, soft supersymmetry breaking parameters and gauge coupling unification. This work was supported in part by the Director, Office of Energy Research, Office of High Energy and Nuclear Physics, Division of High Energy Physics of the U.S. Department of Energy under Contract DE-AC03-76SF00098 and in part by the National Science Foundation under grant PHY-95-14797. Visiting Miller Professor. Permanent address: Laboratoire de Physique Théorique et Hautes Energies (Laboratoire associé au CNRS–URA-D0063), Université Paris-Sud, F-91405 Orsay, France Miller Professor, Fall 1996.