Low energy signals from moduli

We emphasize a string result that in (2,2) superstring compactifications, moduli (massless field corresponding to the deformations of compactified spaces) generically couple to ordinary quarks and leptons in Yukawa-type interactions. They in turn mediate a composition-dependent attractive force between ordinary matter. The range of such a force crucially depends on the mechanism that breaks supersymmetry; if the bare mass of moduli remains zero even after supersymmetry breaking, the strength and the range of such a force is completely determined by the string vacuum and is bound to be on the boundary of present experimental limits. (orig.)