Two-pion exchange in the nucleon-nucleon potential

The two-pion-exchange potential is calculated using experimental ππ, πN and eN information and compared with the Hamada-Johnston and deTourreil-Sprung phenomenological potentials. The calculated potential is found to be in very satisfactory agreement with the phenomenological values at radii greater than 1.2 to 1.5 fm except in the isospin-zero spin-orbit case. The potential is somewhat sensitive to the low-energy I=J=0 ππ interaction, which is still experimentally uncertain.