Poles in Coupled Scattering Amplitudes

Abstract

Elastic scattering amplitudes which have the analytic structure of the Mandelstam representation and which satisfy the unitarity condition and substitution law are severely restricted. Because of these restrictions, poles cannot occur independently and arbitrarily in amplitudes coupled by the unitarity condition. Instead, the locations and residues of poles in coupled amplitudes must satisfy the same relations as do poles in perturbation theory amplitudes.