Meson-mode mixing in the calculation of the nucleon-nucleon interaction.

Abstract

We consider pion exchange between nucleons in the one-boson-exchange model and in a model based upon the use of the quark-quark {ital T} matrices of the Nambu--Jona-Lasinio (NJL) model. We study the relation between the meson-nucleon form factors of the boson-exchange model and the form factors that appear in our application of the NJL model. Previously we indicated that the form factors of the boson-exchange model are not physical quantities. For example, we saw that, while the vertex form factor of the boson-exchange model depends upon a parameter {Lambda}{sub {pi}}=1.3 GeV in the case of pion exchange, the corresponding {ital physical} parameter characterizing the meson-nucleon vertex is {Lambda}{sub {pi}}{congruent}0.8 GeV. In this paper we study how the mixing of the pion and the axial-vector ({ital T}=1) mode affects the value of {lambda}{sub {pi}} needed in our model. We find that the two models of pion exchange in the nucleon-nucleon interaction can be put into excellent agreement if {lambda}{sub {pi}}=0.9 GeV is used.