Regge Poles andSU(3): Particle Classification and High-Energy Scattering

Abstract

An integrated interpretation of the fundamental particle spectrum and the phenomena observed in high-energy scattering is possible within the framework provided by the $\mathrm{SU}\left(3\right)\mathrm{}$ and Regge pole theories of strong interactions. Recent progress in this direction is reviewed with particular emphasis on qualitative predictions and experimental tests. The presence of forward and backward peaks in scattering angular distributions is associated with the existence of certain $\mathrm{SU}\left(3\right)\mathrm{}$ multiplets of mesons and baryons that mediate the reactions as peripheral exchanges. The observed baryons are tentatively classified as Regge recurrences of 1-, 8-, and 10-dimensional $\mathrm{SU}\left(3\right)\mathrm{}$ multiplets. For mesons, recurrences of only 1 and 8 representations are expected. Predictions for charge-exchange processes based on meson Regge exchanges are described in some detail. $\mathrm{SU}\left(3\right)\mathrm{}$ symmetry for the vertices of the Regge exchanges leads to relations that agree with experiment. Scattering in the intermediate momentum range (1-4 BeV/c) is described in terms of an interference model which incorporates direct channel resonances as well as Regge exchange. Structure in forward ${\pi }^{-}p\to {\pi }^{0}n$ scattering and backward ${\pi }^{-}p$ elastic scattering is interpreted by interference model calculations.