Two Pion versus σ-Meson Exchange Potentials

Abstract

The two pion exchange potentials are evaluated by carrying out the numerical integrations of three Feynman parameters in the corresponding Feynman diagrams. The two pion exchange potentials give rise to the attractive force which is quite similar to the effective scalar meson with its mass of m s ≃4.7m π and its strength of at T = 0 channel. However, there is a strong isospin dependence of ( t 1 · t 2 ) 2 which should be different from the phenomenological σ-meson exchange calculations. Therefore, the medium range attraction of the T = 0 nuclear interaction should be due to the two pion exchange processes, but the T = 1 channel is still an open problem.