1,897 research outputs found
Neutron Skin Thickness of 90Zr Determined By Charge Exchange Reactions
Charge exchange spin-dipole (SD) excitations of 90Zr are studied by the
90Zr(p,n) and 90Zr(n,p) reactions at 300 MeV. A multipole decomposition
technique is employed to obtain the SD strength distributions in the cross
section spectra. For the first time, a model-independent SD sum rule value is
obtained: 148+/-12 fm^2. The neutron skin thickness of 90Zr is determined to be
0.07+/-0.04 fm from the SD sum rule value.Comment: 4 pages, 2 figures, submitted to Phys. Rev.
Three-body model calculations for 16C nucleus
We apply a three-body model consisting of two valence neutrons and the core
nucleus C in order to investigate the ground state properties and the
electronic quadrupole transition of the C nucleus. The discretized
continuum spectrum within a large box is taken into account by using a
single-particle basis obtained from a Woods-Saxon potential. The calculated
B(E2) value from the first 2 state to the ground state shows good agreement
with the observed data with the core polarization charge which reproduces the
experimental B(E2) value for C. We also show that the present
calculation well accounts for the longitudinal momentum distribution of
C fragment from the breakup of C nucleus. We point out that the
dominant ( configuration in the ground state of C plays a
crucial role for these agreement.Comment: 5 pages, 3 figures, 3 table
Tensor correlation, pairing interaction and deformation in Ne isotopes and Ne hypernuclei
We study tensor and pairing effects on the quadruple deformation of neon
isotopes based on a deformed Skyrme-Hartree-Fock model with BCS approximation
for the pairing channel. We extend the Skyrme-Hartree-Fock formalism for the
description of single- and double-lambda hypernuclei adopting two different
hyperon-nucleon interactions. It is found that the interplay of pairing and
tensor interactions is crucial to derive the deformations in several neon
isotopes. Especially, the shapes of Ne are studied in details in
comparisons with experimentally observed shapes. Furthermore the deformations
of the hypernuclei are compared with the corresponding neon isotopic cores in
the presence of tensor force. We find the same shapes with somewhat smaller
deformations for single -hypernuclei compared with their core
deformations. It is also pointed out that the latest version of hyperon
interaction, the ESC08b model, having a deeper potential makes
smaller deformations for hypernuclei than those of another NSC97f model.Comment: 13 pages, 5 figures, Physical Review C 2013 in pres
Effect of pairing correlations on incompressibility and symmetry energy in nuclear matter and finite nuclei
The role of superfluidity in the incompressibility and in the symmetry energy
is studied in nuclear matter and finite nuclei. Several pairing interactions
are used: surface, mixed and isovector dependent. Pairing has a small effect on
the nuclear matter incompressibility at saturation density, but the effects are
significant at lower densities. The pairing effect on the centroid energy of
the isoscalar Giant Monopole Resonance (GMR) is also evaluated for Pb and Sn
isotopes by using a microscopic constrained-HFB approach, and found to change
at most by 10% the nucleus incompressibility . It is shown by using the
Local Density Approximation (LDA) that most of the pairing effect on the GMR
centroid come from the low-density nuclear surface.Comment: 9 pages, 6 figure
Designing optimal discrete-feedback thermodynamic engines
Feedback can be utilized to convert information into useful work, making it
an effective tool for increasing the performance of thermodynamic engines.
Using feedback reversibility as a guiding principle, we devise a method for
designing optimal feedback protocols for thermodynamic engines that extract all
the information gained during feedback as work. Our method is based on the
observation that in a feedback-reversible process the measurement and the
time-reversal of the ensuing protocol both prepare the system in the same
probabilistic state. We illustrate the utility of our method with two examples
of the multi-particle Szilard engine.Comment: 15 pages, 5 figures, submitted to New J. Phy
Effects of the Tensor Force on the Multipole Response in Finite Nuclei
We present a thorough analysis of the effects of the tensor interaction on
the multipole response of magic nuclei, using the fully self-consistent Random
Phase Approximation (RPA) model with Skyrme interactions. We disentangle the
modifications to the static mean field induced by the tensor terms, and the
specific features of the residual particle-hole (p-h) tensor interaction, for
quadrupole (2+), octupole (3-), and also magnetic dipole (1+) responses. It is
pointed out that the tensor force has a larger effect on the magnetic dipole
states than on the natural parity states 2+ and 3-, especially at the mean
field level. Perspectives for a better assessment of the tensor force
parameters are eventually discussed
Dominance of Nuclear Processes in the Dissociation of 8B
We study the break-up of 8B in collisions with heavy-ions. The process is
described in terms of inelastic excitations leading to states in the continuum.
The effects of the nuclear and coulomb fields are included on the same
footing in the microscopic construction of the transition matrix elements. The
interplay between coulomb and nuclear excitation processes differs
significantly from the situation encountered in reactions involving systems
close to the stability line. In particular, nuclear excitation is found to
remain predominant at energies well below the coulomb barrier,Comment: TEX file + 11 postscript figure
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