Approximation of the microscopic effective pairing interaction by the off-shell T matrix for free nucleon-nucleon scattering

The effective pairing interaction in the S-1(0) channel as calculated micro scopically within the Brueckner method for a planar slab of nuclear matter by using the separable version of the Paris nucleon-nucleon potential is in vestigated. The effective interaction is determined for the model space inc luding all negative-energy single-particle states. An analysis is performed for two values of the chemical potential, mu = -8 and -4 MeV. It is shown that, to a high precision, the effective interaction can be approximated by the off-shell T matrix for free nucleon-nucleon interaction, the T matrix in question being taken at a negative value of the total energy of two nucl eons E = 2 mu. (C) 2000 MAIK "Nauka/Interperiodica".