TTP95-08 Rho - omega mixing in chiral perturbation theory

In order to calculate the $\rho^0 -\omega$ mixing we extend the chiral couplings of the low-lying vector mesons in chiral perturbation theory to a lagrangian that contains two vector fields. We determine the $p^2$ dependence of the two-point function and recover an earlier result for the on-shell expression.