A dynamical model for correlated two-pion-exchange in the pion-nucleon interaction

Abstract

A microscopic model for the $N\bar{N}\to \ddot{I}€\ddot{I}€$ process is presented in the meson exchange framework, which in the pseudophysical region agrees with available quasiempirical information. The scalar ($\ddot{I}ƒ$) and vector ($\ddot{I}$) piece of correlated two--pion exchange in the pion--nucleon interaction is then derived via dispersion integrals over the unitarity cut. Inherent ambiguities in the method and implications for the description of pion--nucleon scattering data are discussed.

20 pages, 11 postscript figures