  The momentum-dependence of the $\rho^0$-$\omega$ mixing contribution to
charge-symmetry breaking (CSB) in the nucleon-nucleon interaction is compared
in a variety of models. We focus in particular on the role that the structure
of the quark propagator plays in the predicted behaviour of the
$\rho^0$-$\omega$ mixing amplitude. We present new results for a confining
(entire) quark propagator and for typical propagators arising from explicit
numerical solutions of quark Dyson-Schwinger equations. We compare these to
hadronic and free quark calculations. The implications for our current
understanding of CSB experiments is discussed.

Nuclear Theory