not complete. The models of refs. [@GHT92]-[@MTRC94],[@IN94] present the mixed $\rho-\omega$ propagator off-shell, but do not give the necessary simultaneous consistent description of the CSB N-N-vector meson vertices.

Philosophy Of Meson Exchange Potentials
=======================================

The preceeding argument that off-shell meson propagators are not sufficient is entirely based on field theoretic considerations. Clearly, this does not help us to to compute observables, it does not address the question of how one can compute CSB (or any other) observables in nuclear physics. One typically constructs a nucleon-nucleon potential and then computes wavefunctions, hoping that the potentials capture the essential aspects of the underlying field theory. Nevertheless, there is no unambiguous way to construct potentials. Nontrivial assumptions must be made.

Here we will assume that the assumptions underlying phenomenologically successful meson exchange models are reasonable. While one can construct equally successful purely phenomenological models, the meson exchange models make a connection to the spectral properties of the underlying theory. Moreover, the entire question we are investigating—the role of $\rho-\omega$ mixing in CSB effects in nuclear physics—can only be addressed in the context of a potential model which employs vector mesons.

There is a definite philosophy underlying the construction of NN potentials from meson 