How to evaluate cross sections in models where the s-matrix is unitary but does not conserve energy
Jerzy Jurkiewicz, Krzysztof Zalewski · Jagiellonian University Repository (Jagiellonian University) · 1976
The standard time-dependent description of the scattering processes is used to explain that, when the S-matrix does not conserve energy, the coefficient relating the squared modulus of the S-matrix element to the cross-section becomes model-dependent, and the optical theorem does not necessarily follow from the unitarity of the S-matrix. It is suggested that, if one insists on using such models, the optical theorem should be imposed as a constraint and used to fix the model-dependent coefficient.