9 research outputs found
The effective force NL3 revisited
Covariant density functional theory based on the relativistic mean field
(RMF) Lagrangian with the parameter set NL3 has been used in the last ten years
with great success. Now we propose a modification of this parameter set, which
improves the description of the ground state properties of many nuclei and
simultaneously provides an excellent description of excited states with
collective character in spherical as well as in deformed nuclei.Comment: 8 pages, 5 figure
Cranked Relativistic Hartree-Bogoliubov Theory: Formalism and Application to the Superdeformed Bands in the region
Cranked Relativistic Hartree-Bogoliubov theory without and with approximate
particle number projection by means of the Lipkin-Nogami method is presented in
detail as an extension of Relativistic Mean Field theory with pairing
correlations to the rotating frame. Pairing correlations are taken into account
by a finite range two-body force of Gogny type. The applicability of this
theory to the description of rotating nuclei is studied in detail on the
example of superdeformed bands in even-even nuclei of the mass
region. Different aspects such as the importance of pairing and particle number
projection, the dependence of the results on the parametrization of the RMF
Lagrangian and Gogny force etc. are investigated in detail. It is shown that
without any adjustment of new parameters the best description of experimental
data is obtained by using the well established parameter sets NL1 for the
Lagrangian and D1S for the pairing force. Contrary to previous studies at spin
zero it is found that the increase of the strength of the Gogny force is not
necessary in the framework of Relativistic Hartree-Bogoliubov theory provided
that particle number projection is performed.Comment: 34 pages, 24 figures, 3 tables, uses Revtex and epsf.sty, submitted
to Nuclear Physics
Shell Effects in Nuclei with Vector Self-Coupling of Omega Meson in Relativistic Hartree-Bogoliubov Theory
Shell effects in nuclei about the stability line are investigated within the
framework of the Relativistic Hartree-Bogoliubov (RHB) theory with
self-consistent finite-range pairing. Using 2-neutron separation energies of Ni
and Sn isotopes, the role of - and -meson couplings on the
shell effects in nuclei is examined. It is observed that the existing
successful nuclear forces (Lagrangian parameter sets) based upon the nonlinear
scalar coupling of -meson exhibit shell effects which are stronger than
suggested by the experimental data. We have introduced nonlinear vector
self-coupling of -meson in the RHB theory. It is shown that the
inclusion of the vector self-coupling of -meson in addition to the
nonlinear scalar coupling of -meson provides a good agreement with the
experimental data on shell effects in nuclei about the stability line. A
comparison of the shell effects in the RHB theory is made with the Hartree-Fock
Bogoliubov approach using the Skyrme force SkP. It is shown that the
oft-discussed shell quenching with SkP is not consistent with the available
experimental data.Comment: 34 pages latex, 18 ps figures, replaced with minor corrections in
some figures, accepted for publication in Phys. Rev.
Continuum effects for the mean-field and pairing properties of weakly bound nuclei
Continuum effects in the weakly bound nuclei close to the drip-line are
investigated using the analytically soluble Poschl-Teller-Ginocchio potential.
Pairing correlations are studied within the Hartree-Fock-Bogoliubov method. We
show that both resonant and non-resonant continuum phase space is active in
creating the pairing field. The influence of positive-energy phase space is
quantified in terms of localizations of states within the nuclear volume.Comment: 27 RevTeX pages, 12 EPS figures included, submitted to Physical
Review