Resonance spins and Regge residues

The diffractive component of the slopes of elastic differential cross sections at intermediate energies is examined in the context of a strong coupling multiperipheral cluster resonance model. The crucial ingredient is the incorporation of resonance spins. Qualitative agreement with πp, Kp, and pp scattering is obtained. We also conjecture a mechanism whereby s-channel helicity can be approximately conserved in elastic but not in certain quasi-elastic diffractive processes. The problem of the extension to NAL-ISR energies is briefly discussed.