4,163 research outputs found
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.
Advection of a passive scalar field by turbulent compressible fluid: renormalization group analysis near
The field theoretic renormalization group (RG) and the operator product
expansion (OPE) are applied to the model of a density field advected by a
random turbulent velocity field. The latter is governed by the stochastic
Navier-Stokes equation for a compressible fluid. The model is considered near
the special space dimension . It is shown that various correlation
functions of the scalar field exhibit anomalous scaling behaviour in the
inertial-convective range. The scaling properties in the RG+OPE approach are
related to fixed points of the renormalization group equations. In comparison
with physically interesting case , at additional Green function
has divergences which affect the existence and stability of fixed points. From
calculations it follows that a new regime arises there and then by continuity
moves into . The corresponding anomalous exponents are identified with
scaling dimensions of certain composite fields and can be systematically
calculated as series in (the exponent, connected with random force) and
. All calculations are performed in the leading one-loop
approximation.Comment: 11pages, 6 figures, LATEX2e. arXiv admin note: substantial text
overlap with arXiv:1611.00327; text overlap with arXiv:1611.0130
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.
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.
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.
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