12,576 research outputs found
Constraining the density dependence of symmetry energy from nuclear masses
Empirically determined values of the nuclear volume and surface symmetry
energy coefficients from nuclear masses are expressed in terms of density
distributions of nucleons in heavy nuclei in the local density approximation.
This is then used to extract the value of the symmetry energy slope parameter
. The density distributions in both spherical and well deformed nuclei
calculated within microscopic framework with different energy density
functionals give MeV. Application of the method also helps
in a precision determination of the neutron skin thickness of nuclei that are
difficult to measure accurately.Comment: 6 pages including 3 figures, accepted in Phys. Rev. C (Rapid Comm.
Symmetry energy of warm nuclear systems
The temperature dependence of the symmetry energy and symmetry free energy
coefficients of infinite nuclear matter and of finite nuclei is investigated.
For infinite matter, both these coefficients are found to have a weaker
dependence on temperature at densities close to saturation; at low but
homogeneous densities, the temperature dependence becomes stronger. For finite
systems, different definitions of symmetry energy coefficients are encountered
in the literature yielding different values. A resolution to this problem is
suggested from a global liquid-drop-inspired fit of the energies and free
energies of a host of nuclei covering the entire periodic table. The hot
nucleus is modeled in a subtracted finite-temperature-Thomas-Fermi framework,
with dynamical surface phonon coupling to nucleonic motion plugged in. Contrary
to infinite nuclear matter, a substantial change in the symmetry energy
coefficients is observed for finite nuclei with temperature.Comment: 12 pages, including 11 figures, appearing in special issue of EPJ-A
on Nuclear Symmetry Energ
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