Breaking Nambu-Goldstone Chiral Symmetries

Abstract

We establish that the nonanalytic behavior of some matrix elements in perturbation theory about a chiral symmetry implies that they can be calculated exactly to leading order in chiral breaking. For other matrix elements, analytic to leading order, we establish the hypothesis of threshold dominance in the chiral limit. As an application of this idea we calculate, to leading order in chiral breaking, the seven baryon-octet mass differences in terms of one parameter.