Generation of baryons and resonances in brokenSU 3 symmetry

Abstract

The dynamical hypothesis of generation of particles via one-particle exchange graphs, that proved. successful in early calculations (1,7), is analysed in the case of baryonic amplitudes. A simple criterion that seems to work in the mesonic case is shown to be unapplicable. More complicated ones are used with the hope that the type of questions being asked are insensitive to detailed arguments. At this stage the main question of the paper is posed: which is the relation between higher symmetries and the analyticity point of view when breakdowns of the former are allowed? It is found that the generation of the resonance decuplet as performed byMartin andWali (6,19) can be understood both in terms of broken SU3 and analyticity, though mixing between representations is rather strong. When the reciprocal bootstrap idea of generating baryons by decuplet exchange is tried, difficulties appear that, in our opinion, are very serious. A model is proposed that generates the baryons via vector meson exchange. It stands the proposed tests better than the reciprocal bootstrap model but is not completely free of difficulties. As a fundamental difference, it predicts a ninth baryon, that belongs to a singlet representation.