Elastic Hadronic Processes, Duality and Absorption

Abstract

This chapter presents a simple qualitative model for hadronic two-body amplitudes. The model combines the two-component theory of duality with the main idea of the absorption model. The qualitative predictions of the model for elastic differential cross sections and polarizations correctly reproduce several interesting regularities of the data. In addition, the chapter explains the presence of dips in nonexotic elastic processes and their absence in exotic reactions. Prior to the introduction of duality into hadron dynamics, high energy hadronic reactions were usually analyzed only in terms of the allowed t-channel exchanges. Duality explains that the s-channel quantum numbers are also relevant at high energies and that the t -channel exchanges should obey constraints that are imposed by the s-channel picture. Several empirical regularities relate the s-channel quantum numbers of hadronic elastic processes and the properties of the corresponding total and elastic cross sections at high energies.