One loop soft supersymmetry breaking terms in superstring effective theories

We perform a systematic analysis of soft supersymmetry breaking terms at the one loop level in a large class of string effective field theories, This includes the so-called anomaly mediated contributions. We illustrate our results for several classes of orbifold models, In particular, we discuss a class of models where soft supersymmetry breaking terms are determined by quasi model independent anomaly mediated contributions, with possibly non-vanishing scalar masses at the one loop level. We show that the latter contribution depends on the detailed prescription of the regularization process which is assumed to represent the Planck scale physics of the underlying fundamental theory. The usual anomaly mediation case with vanishing scaler masses at one loop is not found to be generic. However gaugino masses and A-terms always vanish at tree level if supersymmetry breaking is moduli dominated with the moduli stabilized at self-dual points, whereas the vanishing of the B-term depends on the origin of the Ir-term in the underlying theory. We also discuss the supersymmetric spectrum of O-I and O-II models, as well as a model of gaugino condensation. For reference, explicit spectra corresponding to a Higgs mass of 114 GeV are given, Finally, we address general strategies for distinguishing among these models. (C) 2001 Elsevier Science B.V. All rights reserved.