Low-energy constants from high-energy theorems - art. no. 116005

New constraints on resonance saturation in chiral perturbation theory are i nvestigated. These constraints arise because each consistent saturation sch eme must map to a representation of the full QCD chiral symmetry group. The low-energy constants of chiral perturbation theory are then related by a s et of mixing angles. It is shown that vector meson dominance is a consequen ce of the fact that nature has chosen the lowest-dimensional nontrivial chi ral representation. It is further shown that chiral symmetry places an uppe r bound on the mass of the lightest scalar in the hadron spectrum.