Jirina Stone

Abstract:

This paper presents a further application of a new model for the effective two-body nucleon-nucleon interaction using a density-dependent separable monopole (SMO) interaction. This model has recently been successfully used for calculating the ground-state properties of spherical, doubly closed-shell nuclei from 16O to 208Pb and is used here to calculate properties of infinite symmetric nuclear matter and the beta-stable n + p + e + μ matter of relevance for neutron stars. An equation of state (EOS) is constructed for this and is joined smoothly onto the Baym, Pethick, and Sutherland EOS for baryon number densities below n = 0.1 fm-3 and onto the widely used Bethe-Johnson EOS at n = 0.5 fm-3 Nonrotating, zero-temperature neutron-star models have been calculated for this composite EOS and the results obtained are compared with those for models calculated with the Skyrme effective interaction and with realistic nucleon-nucleon potentials. The SMO interaction is shown to give excellent global agreement with a wide range of expected properties of infinite nuclear matter and of neutron stars.

Abstract:

Additional evidence for the rare kaon decay K+-->pi+nu(nu) has been found in a new data set with comparable sensitivity to the previously reported result. One new event was observed in the pion momentum region examined, 211pi+nu(nu)) = 1.57(+1.75)(-0.82)x10(-10).

Abstract:

We present calculations of ground state properties of spherical, doubly closed-shell nuclei from 16O to 208Pb employing the techniques of many-body perturbation theory using a separable density-dependent monopole interaction. The model gives results in Hartree-Fock order that are of similar quality to other effective density-dependent interactions. In addition, second and third order perturbation corrections to the binding energy are calculated and are found to contribute small, but non-negligible corrections beyond the mean-field result. The perturbation series converges quickly, suggesting that this method may be used to calculate fully correlated wave functions with only second or third order perturbation theory. We discuss the quality of the results and suggest possible methods of improvement.