Energy scales and diffraction scattering

The influence of thresholds on models of diffraction scattering is considered. We use the experimental existence of effective inelastic diffraction and baryon-antibaryon thresholds to conjecture a relationship between the bare Pomeron $P^G$, of the Gribov calculus, the bare Pomeron $P^E$ of recent fits to Fermilab-CERN-ISR elastic data, and a bare Pomeron $\hat{P}$ of intercept ${\hat{\alpha }}_0\simeq 0.85$ utilized in medium-energy two-body and high-energy inclusive phenomenology. A set of energy scales is set up describing approximate regions of validity of various models for diffraction, including the Gribov calculus. An iterative approximation scheme to the $s$- and $t$-channel unitarity equations at small $t$ and large $s$ is described.