  We study a simple 2-d model representing two fields with different mass and a
3-point coupling term. The phase shift in the resonating 2-particle channel is
determined from the energy spectrum obtained in Monte Carlo simulations on
finite lattices. Masses and wave function renormalization constants of the
fields as well as mass and width of the resonance are determined and discussed.
The representation of scattering states in terms of the considered operators is
analysed.
