E. Osnes

Realistic effective interactions for nuclear systems

Abstract A review of perturbative many-body descriptions of several nuclear systems is presented in this report. Examples of systems considered are symmetric and asymmetric nuclear matter and finite nuclei with few valence particles. Our many-body description starts with the most recent meson-exchange potential models for the nucleon-nucleon interaction, an interaction which in turn is used in our perturbative schemes to evaluate the effective interaction for finite nuclei and infinite nuclear matter. A unified perturbative approach based on time-dependent perturbation theory is elaborated. For finite nuclei we present new results for the effective interaction and the energy spectra in the mass areas of oxygen, calcium and tin.

ASYMMETRIC NUCLEAR MATTER AND NEUTRON STAR PROPERTIES

We calculate properties of neutron stars such as mass and radius using a relativistic Dirac-Brueckner-Hartree-Fock approach. Modern meson-exchange potential models are used to evaluate the [ital G] matrix for asymmetric nuclear matter. For pure neutron matter we find the maximum mass to be [ital M][sub max][approx]2.4[ital M][sub [circle dot]] for a radius [ital R][approx]12 km, whereas with a proton fraction of 30% we find [ital M][sub max][approx]2.1[ital M][sub [circle dot]] for a radius [ital R][approx]10.5 km, close to the experimental values. The implications are discussed.

SUPERFLUIDITY IN BETA -STABLE NEUTRON STAR MATTER

In this work we present results for pairing gaps in

Asymmetric Nuclear Matter and Neutron Star Properties

\beta

Effective interactions and the nuclear shell-model

--stable neutron star matter with electrons and muons using a relativistic Dirac--Brueckner--Hartree--Fock approach, starting with modern meson--exchange models for the nucleon--nucleon interaction. Results are given for superconducting

Model-space approach to 1S0 neutron and proton pairing in neutron star matter with the Bonn meson-exchange potentials

^1S_0

On the recoil term in the particle-rotor model☆

protons and

Triplet pairing of neutrons in β-stable neutron star matter

^3P_2

A simple method for evaluating Goldstone diagrams in an angular momentum coupled representation

and

Folded-diagram effective interactions with the Bonn meson-exchange potential model

^1D_2