238 research outputs found
Symmetry energy, unstable nuclei, and neutron star crusts
Phenomenological approach to inhomogeneous nuclear matter is useful to
describe fundamental properties of atomic nuclei and neutron star crusts in
terms of the equation of state of uniform nuclear matter. We review a series of
researches that we have developed by following this approach. We start with
more than 200 equations of state that are consistent with empirical masses and
charge radii of stable nuclei and then apply them to describe matter radii and
masses of unstable nuclei, proton elastic scattering and total reaction cross
sections off unstable nuclei, and nuclei in neutron star crusts including
nuclear pasta. We finally discuss the possibility of constraining the density
dependence of the symmetry energy from experiments on unstable nuclei and even
observations of quasi-periodic oscillations in giant flares of soft gamma-ray
repeaters.Comment: 17 pages, 16 figures, to appear in EPJA special volume on symmetry
energy. arXiv admin note: text overlap with arXiv:1303.450
Proton-nucleus elastic scattering and the equation of state of nuclear matter
We calculate differential cross sections for proton-nucleus elastic
scattering by using a Glauber theory in the optical limit approximation and
nucleon distributions that can be obtained in the framework of macroscopic
nuclear models in a way dependent on the equation of state of uniform nuclear
matter near the saturation density. We find that the peak angle calculated for
unstable neutron-rich nuclei in the small momentum transfer regime increases as
the parameter L characterizing the density dependence of the symmetry energy
decreases. This is a feature associated with the L dependence of the predicted
matter radii.Comment: 11 pages, 3 figures, to be published in Phys. Lett.
The symmetry energy at subnuclear densities and nuclei in neutron star crusts
We examine how the properties of inhomogeneous nuclear matter at subnuclear
densities depend on the density dependence of the symmetry energy. Using a
macroscopic nuclear model we calculate the size and shape of nuclei in neutron
star matter at zero temperature in a way dependent on the density dependence of
the symmetry energy. We find that for smaller symmetry energy at subnuclear
densities, corresponding to larger density symmetry coefficient L, the charge
number of nuclei is smaller, and the critical density at which matter with
nuclei or bubbles becomes uniform is lower. The decrease in the charge number
is associated with the dependence of the surface tension on the nuclear density
and the density of a sea of neutrons, while the decrease in the critical
density can be generally understood in terms of proton clustering instability
in uniform matter.Comment: 13 pages, 9 figures; Fig. 6 corrected, typos correcte
Saturation of nuclear matter and radii of unstable nuclei
We examine relations among the parameters characterizing the phenomenological
equation of state (EOS) of nearly symmetric, uniform nuclear matter near the
saturation density by comparing macroscopic calculations of radii and masses of
stable nuclei with the experimental data. The EOS parameters of interest here
are the symmetry energy S_0, the symmetry energy density-derivative coefficient
L and the incompressibility K_0 at the normal nuclear density. We find a
constraint on the relation between K_0 and L from the empirically allowed
values of the slope of the saturation line (the line joining the saturation
points of nuclear matter at finite neutron excess), together with a strong
correlation between S_0 and L. In the light of the uncertainties in the values
of K_0 and L, we macroscopically calculate radii of unstable nuclei as expected
to be produced in future facilities. We find that the matter radii depend
strongly on L while being almost independent of K_0, a feature that will help
to determine the L value via systematic measurements of nuclear size.Comment: 26 pages, 7 figure
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