110 research outputs found
Testing He density distributions by calculations of total reaction cross-sections of He+Si
Calculations of the He + Si total reaction cross sections at
intermediate energies are performed on the basis of the Glauber-Sitenko
microscopic optical-limit model. The target-nucleus density distribution is
taken from the electron-nucleus scattering data, and the He densities
are used as they are derived in different models. The results of the
calculations are compared with the existing experimental data. The effects of
the density tails of the projectile nuclei as well as the role of shell
admixtures and short-range correlations are analyzed.Comment: 10 pages, 5 figures. Submitted to the International Journal of Modern
Physics
Polarized Proton Scattering at 134 Mev from Deformed Rare Earth Nuclei
This work was supported by the National Science Foundation Grants NSF PHY 78-22774 A03, NSF PHY 81-14339, and by Indiana Universit
Polarized Proton Scattering at 134 MeV from 154-Sm and 166-Er
This work was supported by the National Science Foundation Grant NSF PHY 81-14339 and by Indiana Universit
Mass Dependence of M3Y-Type Interactions and the Effects of Tensor Correlations
The mass dependence of the M3Y-type effective interactions and the effects of
tensor correlations are examined. Two-body nuclear matrix elements are obtained
by the lowest order constrained variational (LOCV) technique with and without
tensor correlations. We have found that the tensor correlations are important
especially in the triplet-even (TE) and tensor-even (TNE) channels in order to
reproduce the G-matrix elements obtained previously. Then M3Y-type potentials
for inelastic scattering are obtained by fitting our two-body matrix elements
to those of a sum of Yukawa functions for the mass numbers A=24, A=40 and A=90.Comment: 13 pages, 6 table
Charge density distributions and related form factors in neutron-rich light exotic nuclei
Charge form factors corresponding to proton density distributions in exotic
nuclei, such as He, Li, B and Be are calculated
and compared. The results can be used as tests of various theoretical models
for the exotic nuclei structure in possible future experiments using a
colliding electron-exotic nucleus storage ring. The result of such a comparison
would show the effect of the neutron halo or skin on the proton distributions
in exotic nuclei.Comment: 11 pages, 4 figures, to be published in International Journal of
Modern Physics
Quasi-Local Density Functional Theory and its Application within Extended Thomas-Fermi Approximation
A generalization of the Density Functional Theory is proposed. The theory
developed leads to single-particle equations of motion with a quasi-local
mean-field operator, which contains a quasi-particle position-dependent
effective mass and a spin-orbit potential. The energy density functional is
constructed using the Extended Thomas-Fermi approximation. Within the framework
of this approach the ground-state properties of the doubly magic nuclei are
considered. The calculations have been performed using the finite-range Gogny
D1S force. The results are compared with the exact Hartree-Fock calculations
Gamow-Teller strength in 54Fe and 56Fe
Through a sequence of large scale shell model calculations, total
Gamow-Teller strengths ( and ) in Fe and Fe are
obtained. They reproduce the experimental values once the operator
is quenched by the standard factor of . Comparisons are made with recent
Shell Model Monte Carlo calculations. Results are shown to depend critically on
the interaction. From an analysis of the GT+ and GT strength functions it is
concluded that experimental evidence is consistent with the sum rule.Comment: 6 pages, RevTeX 3.0 using psfig, 7 Postscript figures included using
uufile
Folding model analysis of elastic and inelastic proton scattering on Sulfur isotopes
The folding formalism for the nucleon-nucleus optical potential and inelastic
form factor is applied to study elastic and inelastic proton scattering on
30-40S isotopes. A recently developed realistic density dependent M3Y
interaction, well tested in the folding analysis of nucleus-nucleus elastic and
inelastic scattering, is used as effective NN interaction. The nuclear ground
state and transition densities (for the 2+ excitations in Sulfur isotopes) are
obtained in the Hartree-Fock-BCS and QRPA approaches, respectively. The best
fit ratios of transition moments Mn/Mp for the lowest 2+ states in Sulfur
isotopes are compared to those obtained earlier in the DWBA analysis of the
same data using the same structure model and inelastic form factors obtained
with the JLM effective interaction. Our folding+DWBA analysis has shown quite a
strong isovector mixing in the elastic and inelastic scattering channels for
the neutron rich 38,40S nuclei. In particular, the relative strength of the
isovector part of the transition potential required by the inelastic p+38S data
is significantly stronger than that obtained with the corresponding QRPA
transition density.Comment: 24 pages, 11 figures, accepted for publication in Nucl. Phys.
Calculations of He+p elastic scattering cross sections using folding approach and high-energy approximation for the optical potential
Calculations of microscopic optical potentials (OP's) (their real and
imaginary parts) are performed to analyze the He+p elastic scattering data
at a few tens of MeV/nucleon (MeV/N). The OP's and the cross sections are
calculated using three model densities of He. Effects of the regularization
of the NN forces and their dependence on nuclear density are investigated.
Also, the role of the spin-orbit terms and of the non-linearity in the
calculations of the OP's, as well as effects of their renormalization are
studied. The sensitivity of the cross sections to the nuclear densities was
tested and one of them that gives a better agreement with the data was chosen.Comment: 13 pages, 11 figures, to be published in Eur. Phys. J.
Electron Capture Strength for {60,62}Ni and {58,60,62,64}Ni(p,n){58,60,62,64}Cu reactions at 134.3 MeV
Background: The strength of electron capture for medium mass nuclei has a
significant effect on the evolution of supernovae. There is insufficient
knowledge of these strengths and very little data for important radioactive
nuclei. Purpose: Determine whether it is feasible to obtain EC strength from
studies of T_o+1 excitations in (p,n) reactions, and whether this might yield
information for radioactive nuclei. Methods: Cross sections for the
{58,60,62,64}Ni(p,n){58,60,62,64}Cu reactions were measured over the angular
range of 0.3 deg to 11.6 deg at 134.3 MeV using the IUCF neutron time-of-flight
facility. esults: The T_o+1 excitations in {60,62}Ni were identified by
comparison with inelastic proton scattering spectra, their B(GT) were
extracted, and the corresponding electron capture rates in supernovae were
calculated. Data from the TRIUMF (n,p) experiments at 198 MeV were reanalyzed;
the electron capture rates for the reanalyzed data are in moderately good
agreement with the higher resolution (p,n) results, but differ in detail. The
possibility of future measurements with radioactive nuclei was considered.
Conclusions: It is possible to determine electron capturestrength from (p,n)
experiments. This approach may make it possible to obtain electron capture
strength for radioactive nuclei by studying (p,n) reactions in inverse
kinematics.Comment: Submitted to Physical Review
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