Scalar-isoscalar meson exchange in the calculation of the nucleon-nucleon interaction

Publisher Website
Google Scholar
Abstract
We provide a unified description of (i) scalar-isoscalar exchange in the nucleon-nucleon interaction, (ii) the pion-nucleon sigma term, and (iii) the scalar form factor of the nucleon. Our analysis requires that we specify a parameter that appears in the description of a nucleon valence-quark “core.” Other parameters are fixed either by our analysis of the Nambu–Jona-Lasinio model, or with reference to a recent lattice simulation of QCD in which the scalar form factor of the nucleon was calculated. We find that our model has some predictive power. Once the parameters are fixed, we find that we reproduce the values of the scalar form factor of the nucleon, as determined in the lattice simulation. We also predict the strength of the scalar-isoscalar NN potential for the particular one-boson-exchange model considered here, where the effects of (virtual) Δ excitation are treated in an explicit fashion. However, the overall strength of the force obtained in this work is sensitive to the approximations used in the calculation.