4,128 research outputs found
Core swelling in spherical nuclei: An indication of the saturation of nuclear density
Background: Nuclear radius is one of the most important and basic properties
of atomic nuclei and its evolution is closely related to the saturation of the
nuclear density in the internal region but the systematics of the nuclear radii
for the neutron-rich unstable nuclei is not well known.
Purpose: Motivated by the recent interaction cross section measurement which
indicates the 48Ca core swelling in the neutron-rich Ca isotopes, we explore
the mechanism of the enhancement of the neutron and proton radii for spherical
nuclei.
Methods: Microscopic Hartree-Fock calculations with three sets of Skyrme-type
effective interactions are performed for the neutron-rich Ca, Ni and Sn
isotopes. The total reaction cross sections for the Ca isotopes are evaluated
with the Glauber model to compare them with the recent cross section data.
Results: We obtain good agreement with the measured cross sections and charge
radii. The neutron and proton radii of the various "core" configurations are
extracted from the full Hartree-Fock calculation and discuss the core swelling
mechanism.
Conclusions: The core swelling phenomena occur depending on the properties of
the occupying valence single-neutron states to minimize the energy loss that
comes from the saturation of the densities in the internal region, which
appears to be prominent in light nuclei such as Ca isotopes.Comment: 6 pages, 4 figures, to appear in a Rapid Communication in Phys. Rev.
Probing neutron-skin thickness with total reaction cross sections
We analyze total reaction cross sections, , for exploring their
sensitivity to the neutron-skin thickness of nuclei. We cover 91 nuclei of O,
Ne, Mg, Si, S, Ca, and Ni isotopes. The cross sections are calculated in the
Glauber theory using the density distributions obtained with the
Skyrme-Hartree-Fock method in 3-dimensional coordinate space. Defining a
reaction radius, , to characterize the nuclear size
and target (proton or C) dependence, we find an empirical formula for
expressing with the point matter radius and the skin thickness, and
assess two practical ways of determining the skin thickness from proton-nucleus
values measured at different energies or from values
measured for different targets.Comment: 6 pages, 5 figures, to appear in Phys. Rev.
Mariner Mars 1969 SCAN control subsystem design and analysis
Design and analysis of self correcting automatic navigation system for Mariner Mars spacecraf
Neutrino Induced 4He Break-up Reaction -- Application of the Maximum Entropy Method in Calculating Nuclear Strength Function
The maximum entropy method is examined as a new tool for solving the
ill-posed inversion problem involved in the Lorentz integral transformation
(LIT) method. As an example, we apply the method to the spin-dipole strength
function of 4He. We show that the method can be successfully used for inversion
of LIT, provided the LIT function is available with a sufficient accuracy.Comment: 5 pages, 2 figures. Poster presented by TM at the International
Workshop on Neutrino-Nucleus Interaction in the Few-GeV Region (NuInt15),
Novenber 16-21 2015, Osaka, Japa
Glauber-model analysis of total reaction cross sections for Ne, Mg, Si, and S isotopes with Skyrme-Hartree-Fock densities
A systematic analysis is made on the total reaction cross sections for Ne,
Mg, Si, and S isotopes. The high-energy nucleus-nucleus collision is described
based on the Glauber model. Using the Skyrme-Hartree-Fock method in the
three-dimensional grid-space representation, we determine the nuclear density
distribution for a wide range of nuclei self-consistently without assuming any
spatial symmetry. The calculated total reaction cross sections consistently
agree with the recent cross section data on NeC collision at
240\,MeV, which makes it possible to discuss the radius and deformation of
the isotopes. The total reaction cross sections for MgC, SiC
and SC cases are predicted for future measurements. We also find that
the high-energy cross section data for O, Ne, and Mg isotopes on a C
target at around 1000\,MeV can not be reproduced consistently with the
corresponding data at 240\,MeV.Comment: 10 pages, 14 figure
Monopole Excitation to Cluster States
We discuss strength of monopole excitation of the ground state to cluster
states in light nuclei. We clarify that the monopole excitation to cluster
states is in general strong as to be comparable with the single particle
strength and shares an appreciable portion of the sum rule value in spite of
large difference of the structure between the cluster state and the
shell-model-like ground state. We argue that the essential reasons of the large
strength are twofold. One is the fact that the clustering degree of freedom is
possessed even by simple shell model wave functions. The detailed feature of
this fact is described by the so-called Bayman-Bohr theorem which tells us that
SU(3) shell model wave function is equivalent to cluster model wave function.
The other is the ground state correlation induced by the activation of the
cluster degrees of freedom described by the Bayman-Bohr theorem. We
demonstrate, by deriving analytical expressions of monopole matrix elements,
that the order of magnitude of the monopole strength is governed by the first
reason, while the second reason plays a sufficient role in reproducing the data
up to the factor of magnitude of the monopole strength. Our explanation is made
by analysing three examples which are the monopole excitations to the
and states in O and the one to the state in C.
The present results imply that the measurement of strong monopole transitions
or excitations is in general very useful for the study of cluster states.Comment: 11 pages, 1 figure: revised versio
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