Meson–meson interactions and Regge propagators

By a reformulation of the loop expansion in the Resonance-Spectrum Expansion amplitude for meson–meson scattering, in terms of s-channel exchange of families of propagator modes, we obtain a formalism which allows for a wider range of applications. The connection with the unitarized amplitudes employed in some chiral theories is discussed. We also define an alternative for the Regge spectra and indicate how this may be observed in experiment.