74 research outputs found
Relativistic Structure of the Nucleon Self-Energy in Asymmetric Nuclei
The Dirac structure of the nucleon self-energy in asymmetric nuclear matter
cannot reliably be deduced from the momentum dependence of the single-particle
energies. It is demonstrated that such attempts yield an isospin dependence
with even a wrong sign. Relativistic studies of finite nuclei have been based
on such studies of asymmetric nuclear matter. The effects of these isospin
components on the results for finite nuclei are investigated.Comment: 9 pages, Latex 4 figures include
Dirac Hartree-Fock for Finite Nuclei Employing realistic Forces
We discuss two different approximation schemes for the self-consistent
solution of the {\it relativistic} Brueckner-Hartree-Fock equation for finite
nuclei. In the first scheme, the Dirac effects are deduced from corresponding
nuclear matter calculations, whereas in the second approach the local-density
approximation is used to account for the effects of correlations. The results
obtained by the two methods are very similar. Employing a realistic
one-boson-exchange potential (Bonn~A), the predictions for energies and radii
of O and Ca come out in substantially better agreement with
experiment as compared to non-relativistic approaches. As a by-product of our
study, it turns out that the Fock exchange-terms, ignored in a previous
investigation, are not negligible.Comment:
Self-Consistent Relativistic Calculation of Nucleon Mean Free Path
We present a fully self-consistent and relativistic calculation of the
nucleon mean free path in nuclear matter and finite nuclei. Starting from the
Bonn potential, the Dirac-Brueckner-Hartree-Fock results for nuclear matter are
parametrized in terms of an effective - Lagrangian suitable for
the relativistic density-dependent Hartree-Fock (RDHF) approximation. The
nucleon mean free path in nuclear matter is derived from this effective
Lagrangian taking diagrams up to fourth-order into account. For the nucleon
mean free path in finite nuclei, we make use of the density determined by the
RDHF calculation in the local density approximation. Our microscopic results
are in good agreement with the empirical data and predictions by Dirac
phenomenology.Comment: 16 pages RevTex and 6 figures (paper, available upon request from
[email protected]) UI-NTH-931
- âŠ