Dynamical Determination of the Fundamental Couplings

We demonstrate that supergravity models containing the Standard Model, dilaton and modulus naturally lead to dynamical symmetry breaking with excellent phenomenology. We assume primordial supersymmetry breaking in the form of a constant contribution to the superpotential. String inspired relations link fundamental couplings to the dilaton vev. We specialize to a class of models inspired by the $4$-$D$ fermionic string. Non-renormalizable terms in the superpotential naturally produce the Higgs mixing parameter $\mu$ suitable for our mechanism. We discuss extensions and limitations of our approach.