29,416 research outputs found
Sensitivity of neutron radii in the sigma_-$ rho_ coupling corrections in relativistic mean field theory
We study the sensitivity of the neutron skin thickness, , in a Pb
nucleus to the addition of nucleon-sigma-rho coupling corrections to a
selection (PK1, NL3, S271, Z271) of interactions in relativistic mean field
model. The PK1 and NL3 effective interactions lead to a minimum value of =
0.16 fm in comparison with the original value of = 0.28 fm. The S271 and
Z271 effective interactions yield even smaller values of = 0.11 fm, which
are similar to those for nonrelativistic mean field models. A precise
measurement of the neutron radius, and therefore , in Pb will place
an important constraint on both relativistic and nonrelativistic mean field
models. We also study the correlation between the radius of a 1.4 solar-mass
neutron star and .Comment: 40 pages 13 figures. to be published in Physical Review
The relativistic continuum Hartree-Bogoliubov description of charge-changing cross section for C,N,O and F isotopes
The ground state properties including radii, density distribution and one
neutron separation energy for C, N, O and F isotopes up to the neutron drip
line are systematically studied by the fully self-consistent microscopic
Relativistic Continuum Hartree-Bogoliubov (RCHB) theory. With the proton
density distribution thus obtained, the charge-changing cross sections for C,
N, O and F isotopes are calculated using the Glauber model. Good agreement with
the data has been achieved. The charge changing cross sections change only
slightly with the neutron number except for proton-rich nuclei. Similar trends
of variations of proton radii and of charge changing cross sections for each
isotope chain is observed which implies that the proton density plays important
role in determining the charge-changing cross sections.Comment: 10 pages, 4 figure
Particles in classically forbidden area, neutron skin and halo, and pure neutron matter in Ca isotopes
The nucleon density distributions and the thickness of pure neutron matter in
Ca isotopes were systematically studied using the Skyrme-Hartree-Fock model
(SHF) from the -stability line to the neutron drip-line. The pure
neutron matter, related with the neutron skin or halo, was shown to depend not
only on the Fermi levels of the neutrons but also on the orbital angular
momentum of the valence neutrons. New definitions for the thickness of pure
neutron matter are proposed.Comment: 6 pages, 5 figure
Multi chiral-doublets in one single nucleus
Adiabatic and configuration-fixed constraint triaxial relativistic mean field
(RMF) approaches are developed for the first time and a new phenomenon, the
existence of multi chiral-doublets (MD), i.e., more than one pairs of
chiral doublets bands in one single nucleus, is suggested for nuclei in A~100
region, typically for Rh, based on the triaxial deformations together
with their corresponding proton and neutron configurations.Comment: 10 pages, 4 figure
Energy-dependent Lorentz covariant parameterization of the NN interaction between 50 and 200 MeV
For laboratory kinetic energies between 50 and 200 MeV, we focus on
generating an energy-dependent Lorentz covariant parameterization of the
on-shell nucleon-nucleon (NN) scattering amplitudes in terms of a number of
Yukawa-type meson exchanges in first-order Born approximation. This
parameterization provides a good description of NN scattering observables in
the energy range of interest, and can also be extrapolated to energies between
40 and 300 MeV.Comment: 18 pages, 7 figures, Final version accepted by Physics Review
Effective field theory for triaxially deformed nuclei
Effective field theory (EFT) is generalized to investigate the rotational
motion of triaxially deformed even-even nuclei. A Hamiltonian, called the
triaxial rotor model (TRM), is obtained up to next-to-leading order (NLO)
within the EFT formalism. Its applicability is examined by comparing with a
five-dimensional collective Hamiltonian (5DCH) for the description of the
energy spectra of the ground state and band in Ru isotopes. It is
found that by taking into account the NLO corrections, the ground state band in
the whole spin region and the band in the low spin region are well
described. The results presented here indicate that it should be possible to
further generalize the EFT to triaxial nuclei with odd mass number.Comment: 21 pages, 9 figure
Behavior of the collective rotor in nuclear chiral motion
The behavior of the collective rotor in the chiral motion of triaxially
deformed nuclei is investigated using the particle rotor model by transforming
the wave functions from the -representation to the -representation. After
examining the energy spectra of the doublet bands and their energy differences
as functions of the triaxial deformation, the angular momentum components of
the rotor, proton, neutron, and the total system are investigated. Moreover,
the probability distributions of the rotor angular momentum (-plots) and
their projections onto the three principal axes (-plots) are analyzed. The
evolution of the chiral mode from a chiral vibration at the low spins to a
chiral rotation at high spins is illustrated at triaxial deformations
and .Comment: 21 pages, 6 figure
Spherical Relativistic Hartree theory in a Woods-Saxon basis
The Woods-Saxon basis has been suggested to replace the widely used harmonic
oscillator basis for solving the relativistic mean field (RMF) theory in order
to generalize it to study exotic nuclei. As examples, relativistic Hartree
theory is solved for spherical nuclei in a Woods-Saxon basis obtained by
solving either the Schr\"odinger equation or the Dirac equation (labelled as
SRHSWS and SRHDWS, respectively and SRHWS for both). In SRHDWS, the negative
levels in the Dirac Sea must be properly included. The basis in SRHDWS could be
smaller than that in SRHSWS which will simplify the deformed problem. The
results from SRHWS are compared in detail with those from solving the spherical
relativistic Hartree theory in the harmonic oscillator basis (SRHHO) and those
in the coordinate space (SRHR). All of these approaches give identical nuclear
properties such as total binding energies and root mean square radii for stable
nuclei. For exotic nuclei, e.g., Ca, SRHWS satisfactorily reproduces the
neutron density distribution from SRHR, while SRHHO fails. It is shown that the
Woods-Saxon basis can be extended to more complicated situations for exotic
nuclei where both deformation and pairing have to be taken into account.Comment: 12 pages, 9 figure
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