Chiral-quark-gluon description of the nuclear force.

Abstract

We discuss the restoration of the chiral symmetry in the case of the N-N interaction on the basis of the cloudy bag model. A quantum-chromodynamics-based many-body theory of confined quarks, confined gluons, and pions is developed. In terms of the Green's functions and vertex functions of these fields, the energy shift due to gluon and pion exchange between quarks is calculated systematically and the short-range and long-range parts of the effective nuclear potential are obtained. For the short-range part, a soft repulsive core is obtained using the cloudy bag model parameters and the main contribution comes from the gluon exchange, as expected. The height of the core, however, is sensitive to the (poorly determined) subtraction required to remove the kinetic energy of the relative N-N motion. For the long-range part, an explicit formula, which is the same as one-pion-exchange potential, is obtained, but the strength of this part is 30% lower than that of one-pion-exchange potential when ${f}_{\ensuremath{\pi}}$ is chosen as 93.0 MeV.