Spectroscopy and renormalization group flow of a lattice Nambu-Jona-Lasinio model

We investigate a lattice Nambu--Jona-Lasinio model both by the Monte Carlo method and Schwinger-Dyson equations. A comparison allows the discussion of finite-size effects and the extra- polation to infinite volume. We pay special attention to the identification of particles and resonances. This enables us to discuss renormalization group flows in the neighborhood of the critical coupling where the chiral-symmetry-breaking phase transition takes place. In no region of the bare parameter space do we find renormalizability for the model.