The S-matrix of the kinks of the model

We consider the particle-kink and kink-kink S-matrix elements of the two-dimensional (ψψ)2 model, where the Majorana spinor ψ is an O(N) isovector. Our results confirm many qualitative ideas about the model, including the mass spectrum, the decoupling at N = 4, and the isospinor nature of the kinks.