Pion rescattering operator in the<i>S</i>-matrix approach
Pion rescattering operator in the<i>S</i>-matrix approach
The pion re-scattering operator for pion production, derived recently in time-ordered perturbation theory, is compared with the one following from the simple S-matrix construction. We show that this construction is equivalent to the on-shell approximation introduced in previous papers. For a realistic NN interaction, the S-matrix approach, and its simplified …