Intermediate--range nucleon--nucleon potential

We present results of a calculation of the two-pion-exchange contribution to the nucleon-nucleon potential, which when supplemented by potentials from exchange of the three-pion boson resonances should be expected to give the intermediate-range nucleon-nucleon interaction (say, in the vicinity of 1 fm). The calculated potentials are in fair agreement with the phenomenological potentials. Our calculation differs from previous calculations in that the NN̄→ππ amplitudes we use as our input are in agreement with the most recent data on π N scattering and ππ phase shifts. A surprising feature of our results is the sensitivity of the resulting potential to permissible changes in those amplitudes dominated by the ρ meson---an uncertainty in the potential which has heretofore been overlooked. We also find that the potential is not as energy-independent as previous calculations suggest.