Pions and kaons in QCD

Abstract
From reliable numerical solutions of an approximate Dyson-Schwinger equation for the quark propagator, we obtain values of the pion and kaon decay constants that differ significantly from those obtained recently by Munczek and McKay using ad hoc quark mass functions. We present arguments that the Pagels-Stokar formula should not be used to estimate the pseudoscalar-meson decay constants when chiral symmetry is broken.