Spin-orbit splitting in neutron drops

Technical Report · Tue Aug 01 04:00:00 EDT 1995

DOI:https://doi.org/10.2172/166463· OSTI ID:166463

Pieper, S. C.; Pandharipande, V. R.; Ravenhall, D. G.

Hartree-Fock calculations of very neutron-rich nuclei are an essential source of input for calculations of the properties of neutron-star crusts. The Hartree-Fock calculations often use Skyrme models whose parameters are determined by fits to known (hence not neutron-rich) nuclei and extrapolations to the N >> Z case. The Vautherin and Brink (VB) prescription for the isospin dependence of the spin-orbit potential, V{sub so}, is usually used; this is based on the assumption that most of V{sub so} comes from a short-range L{center_dot}S nucleon-nucleon interaction. In 1993 we showed that more than half of the spin-orbit splitting in {sup 15}N comes from long-range three-nucleon potentials and correlations, which violate the VB assumption. To investigate the isospin dependence of the spin-orbit splitting, we made calculations of the type described in Sec. B.d for systems of 7 (p-wave splitting) and 19 (d-wave) neutrons. The neutrons were confined in external potentials that were adjusted to give physically reasonable densities. We find that the spin-orbit splitting of these drops is less than half the {sup 15}N value. These values can be used to determine an isospin dependence of V{sub so} that is very different from that of VB. Hartree-Fock calculations of known spin-orbit splittings in nuclei with N significantly different from Z are now being made with this new prescription.

• Research Organization: Argonne National Lab., IL (United States)
• OSTI ID: 166463
• Report Number(s): ANL--95/14; ON: DE96000985
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
HARTREE-FOCK METHOD
L-S COUPLING
NEUTRON STARS
NITROGEN 15
NUCLEAR STRUCTURE
NUCLEON-NUCLEON INTERACTIONS
NUCLEON-NUCLEON POTENTIAL
PROGRESS REPORT