Non-perturbative solution of metastable scalar models
  Schwinger-Dyson equations for propagators are solved for the scalar $\Phi^3$ theory and massive Wick-Cutkosky model.   With the help of integral representation the results are obtained directly in Minkowski space in and beyond bare vertex approximation. Various renormalization scheme are employed which differ by the finite strength field renormalization function $Z$ . The $S-$matrix is puzzled from the Green's function and the effect of truncation of the DSEs is studied. Independently on the approximation the numerical solution breaks down for certain critical value of the coupling constant, for which the on-shell renormalized propagator starts to develop the unphysical singularity at very high space-like square of momenta. 
V. Sauli