3,906 research outputs found
Surface properties of neutron-rich exotic nuclei: A source for studying the nuclear symmetry energy
We study the correlation between the thickness of the neutron skin in finite
nuclei and the nuclear symmetry energy for isotopic chains of even-even Ni, Sn,
and Pb nuclei in the framework of the deformed self-consistent mean-field
Skyrme HF+BCS method. The symmetry energy, the neutron pressure and the
asymmetric compressibility in finite nuclei are calculated within the coherent
density fluctuation model using the symmetry energy as a function of density
within the Brueckner energy-density functional. The mass dependence of the
nuclear symmetry energy and the neutron skin thickness are also studied
together with the role of the neutron-proton asymmetry. A correlation between
the parameters of the equation of state (symmetry energy and its density slope)
and the neutron skin is suggested in the isotopic chains of Ni, Sn, and Pb
nuclei.Comment: 13 pages, 10 figures. Accepted for publication in Phys. Rev.
Scaling Functions and Superscaling in Medium and Heavy Nuclei
The scaling function for medium and heavy nuclei with
for which the proton and neutron densities are not similar is constructed
within the coherent density fluctuation model (CDFM) as a sum of the proton and
neutron scaling functions. The latter are calculated in the cases of Ni,
Kr, Sn, and Au nuclei on the basis of the corresponding
proton and neutron density distributions which are obtained in deformed
self-consistent mean-field Skyrme HF+BCS method. The results are in a
reasonable agreement with the empirical data from the inclusive electron
scattering from nuclei showing superscaling for negative values of ,
including those smaller than -1. This is an improvement over the relativistic
Fermi gas (RFG) model predictions where becomes abruptly zero for
. It is also an improvement over the CDFM calculations made in
the past for nuclei with assuming that the neutron density is equal
to the proton one and using only the phenomenological charge density.Comment: 4 pages, 1 figure, ReVTeX, accepted for publication in Phys. Rev.
Symmetry energy of deformed neutron-rich nuclei
The symmetry energy, the neutron pressure and the asymmetric compressibility
of deformed neutron-rich even-even nuclei are calculated on the examples of Kr
and Sm isotopes within the coherent density fluctuation model using the
symmetry energy as a function of density within the Brueckner energy-density
functional. The correlation between the thickness of the neutron skin and the
characteristics related with the density dependence of the nuclear symmetry
energy is investigated for isotopic chains of these nuclei in the framework of
the self-consistent Skyrme-Hartree-Fock plus BCS method. Results for an
extended chain of Pb isotopes are also presented. A remarkable difference is
found in the trend followed by the different isotopic chains: the studied
correlations reveal a smoother behavior in the Pb case than in the other cases.
We also notice that the neutron skin thickness obtained for Pb with
SLy4 force is found to be in a good agreement with recent data.Comment: 14 pages, 10 figures, 2 tables, accepted for publication in Physical
Review
Superscaling in Nuclei: A Search for Scaling Function Beyond the Relativistic Fermi Gas Model
We construct a scaling function for inclusive electron
scattering from nuclei within the Coherent Density Fluctuation Model (CDFM).
The latter is a natural extension to finite nuclei of the Relativistic Fermi
Gas (RFG) model within which the scaling variable was
introduced by Donnelly and collaborators. The calculations show that the
high-momentum components of the nucleon momentum distribution in the CDFM and
their similarity for different nuclei lead to quantitative description of the
superscaling in nuclei. The results are in good agreement with the experimental
data for different transfer momenta showing superscaling for negative values of
, including those smaller than -1.Comment: 16 pages, 5 figures, submitted for publication to Phys. Rev.
Confinement in the Abelian-Higgs-type theories: string picture and field correlators
Field correlators and the string representation are used as two complementary
approaches for the description of confinement in the SU(N)-inspired dual
Abelian-Higgs-type model. In the London limit of the simplest, SU(2)-inspired,
model, bilocal electric field-strength correlators have been derived with
accounting for the contributions to these averages produced by closed dual
strings. The Debye screening in the plasma of such strings yields a novel
long-range interaction between points lying on the contour of the Wilson loop.
This interaction generates a Luescher-type term, even when one restrics oneself
to the minimal surface, as it is usually done in the bilocal approximation to
the stochastic vacuum model. Beyond the London limit, it has been shown that a
modified interaction appears, which becomes reduced to the standard Yukawa one
in the London limit. Finally, a string representation of the SU(N)-inspired
model with the theta-term, in the London limit, can be constructed.Comment: 17 pages, no figures, REVTeX 4; Invited contribution to the
collection of articles devoted to the 70th birthday of Yu.A. Simono
Superscaling and Neutral Current Quasielastic Neutrino-Nucleus Scattering beyond the Relativistic Fermi Gas Model
The superscaling analysis is extended to include quasielastic (QE) scattering
via the weak neutral current of neutrinos and antineutrinos from nuclei. The
scaling function obtained within the coherent density fluctuation model (used
previously in calculations of QE inclusive electron and charge-changing (CC)
neutrino scattering) is applied to neutral current neutrino and antineutrino
scattering with energies of 1 GeV from C with a proton and neutron
knockout (u-channel inclusive processes). The results are compared with those
obtained using the scaling function from the relativistic Fermi gas model and
the scaling function as determined from the superscaling analysis (SuSA) of QE
electron scattering.Comment: 10 pages, 6 figures, published in Phys. Rev.
Superscaling in dilute Fermi gas and its relation to general properties of the nucleon momentum distribution in nuclei
The superscaling observed in inclusive electron scattering is described
within the dilute Fermi gas model with interaction between the particles. The
comparison with the relativistic Fermi gas (RFG) model without interaction
shows an improvement in the explanation of the scaling function in
the region , where the RFG result is . It is found
that the behavior of for depends on the particular
form of the general power-law asymptotics of the momentum distribution
at large . The best agreement with the empirical
scaling function is found for in agreement with the asymptotics
of in the coherent density fluctuation model where . Thus,
superscaling gives information about the asymptotics of and the NN
forces.Comment: 6 pages, 5 figures, accepted for publication in Physical Review
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