Electromagnetic properties of stable particles and resonances according to the unitary symmetry theory

Abstract

We show that a theory whoseSU3-invariant strong interactions are perturbed by electromagnetic interactions alone may be obtained formally by a certain unitary transformation of a theory whoseSU3-invariant strong interactions are perturbed by merely charge-independent interactions. By exploiting readily available information on the latter theory, we can give a rapid derivation of relationships between the electromagnetic properties of various particles and resonances. While many new results are presented, principal emphasis is on the power of the method and on the recognition of the precise nature of the assumptions necessary for the derivation of results. For example, of the seven familiar relations between the magnetic moments of baryons only two require use of the assumption that magnetic moments depend linearly on the electromagnetic charge-current density; the others exemplify relations which hold in identical form for all electromagnetic properties of baryons — electric and magnetic form factors, electromagnetic self-energies, Compton scattering amplitudes etc.