Implication of decoupling effects for one-loop corrected effective actionsfrom superstring theory

We study the decoupling effects in one-loop corrected N = 1 supersymmetric theory with gauge neutral chiral superfields, by calculating the one-loop c orrected effective Lagrangian that involves light and heavy fields with the mass scale M, and subsequently eliminating heavy fields by their equations of motion. In addition to new nonrenormalizable couplings, we determine th e terms that grow as log M. In a model derived from superstring theory, the se terms can significantly modify low-energy predictions for the effective couplings of light fields. For example, in a class of heterotic superstring vacua with an anomalous U(1) the vacuum restabilization introduces such de coupling effects which in turn correct the low energy predictions for certa in couplings by 10-50%.