Dynamical model for correlated two-pion exchange in theNNinteraction

A dynamical model for S- and P-wave correlated two-pion exchange between two nucleons is presented, starting from corresponding NN{}{→}{π}{π} amplitudes in the pseudophysical region, which have been constructed from nucleon and {Δ}-isobar exchange Born terms and a meson exchange model of {π}{π} scattering which satisfactorily describes the empirical {π}{π} data. It is demonstrated that the results have quite different characteristics, in both strength and range, compared to (sharp mass) {σ}', {ρ} exchange as used in the Bonn potential. Consequences for the description of high partial wave NN scattering phase shifts are discussed.