Violation of the Equivalence Principle in String Dilaton Theories

We study violations of the weak equivalence principle in the context of string dilaton theories. In these models some fundamental constants become spaceas well as time-dependent. We show that although universality of free fall (UFF) experiments set bounds on parameters that govern the cosmological evolution of the scalar fields, these are strongly relaxed when considering the space dependent behavior of the scalar field. We also analyze the Oklo bound on the variation of the fine structure constant. Conversely, including the space-dependent solution of the dilaton field, does not affect the restrictions on the free parameters of the model. Finally, consequences on the relevance of experiments on UFF are reanalyzed. PACS NUMBERS: 4.50+h, 4.80 Cc, 98.80Cq