ON-MASS-SHELL GAUGINO CONDENSATION IN Z(N) ORBIFOLD COMPACTIFICATIONS

We discuss non-perturbative aspects of string effective field theories with N = 1 supersymmetry in four dimensions. By the use of a scalar p otential, which is on-shell invariant under the supersymmetric duality of the dilaton, we study gaugino, condensation in (2,2) symmetric Z(N ) orbifold compactifications. The duality under consideration relates a two-form antisymmetric tensor to a pseudoscalar. We show that our ap proach is independent of the superfield-representation of the dilaton and preserves the U(l)(PQ) Peccei-Quinn symmetry exactly.