447 research outputs found
Potential inversion with subbarrier fusion data revisited
We invert experimental data for heavy-ion fusion reactions at energies well
below the Coulomb barrier in order to directly determine the internucleus
potential between the colliding nuclei. In contrast to the previous
applications of the inversion formula, we explicitly take into account the
effect of channel couplings on fusion reactions, by assuming that fusion cross
sections at deep subbarrier energies are governed by the lowest barrier in the
barrier distribution. We apply this procedure to the O +Sm and
O +Pb reactions, and find that the inverted internucleus
potential are much thicker than phenomenological potentials. A relation to the
steep fall-off phenomenon of fusion cross sections recently found at deep
subbarrier energies is also discussed.Comment: 5 pages, 3 eps figure
Reaction cross sections of the deformed halo nucleus 31Ne
Using the Glauber theory, we calculate reaction cross sections for the
deformed halo nucleus Ne. To this end, we assume that the Ne
nucleus takes the Ne + structure. In order to take into account the
rotational excitation of the core nucleus Ne, we employ the
particle-rotor model (PRM). We compare the results to those in the adiabatic
limit of PRM, that is, the Nilsson model, and show that the Nilsson model works
reasonably well for the reaction cross sections of Ne. We also
investigate the dependence of the reaction cross sections on the ground state
properties of Ne, such as the deformation parameter and the p-wave
component in the ground state wave function.Comment: 7 pages, 6 eps figure
Deformation and weak decay of Lambda hypernuclei
We use the self-consistent mean-field theory to discuss the ground state and
decay properties of hypernuclei. We first discuss the deformation of
hypernuclei using the relativistic mean-field (RMF) approach. We show
that, although most of hypernuclei have a similar deformation parameter to the
core nucleus, the shape of Si is drastically altered, from oblately
deformed to spherical, if a particle is added to this nucleus. We
then discuss the pionic weak decay of neutron-rich hypernuclei using
the Skyrme Hartree-Fock + BCS method. We show that, for a given isotope chain,
the decay rate increases as a function of mass number, due to the strong
neutron-proton interaction.Comment: A talk given at Sendai International Symposium on Strangeness Nuclear
and Hadronic Systems (SENDAI08), Dec. 15-18, 2008, Sendai, Japa
Iterative solution of a Dirac equation with inverse Hamiltonian method
We solve a singe-particle Dirac equation with Woods-Saxon potentials using an
iterative method in the coordinate space representation. By maximizing the
expectation value of the inverse of the Dirac Hamiltonian, this method avoids
the variational collapse, in which an iterative solution dives into the Dirac
sea. We demonstrate that this method works efficiently, reproducing the exact
solutions of the Dirac equation.Comment: 4 pages, 3 figure
Effects of finite width of excited states on heavy-ion sub-barrier fusion reactions
We discuss the effects of coupling of the relative motion to nuclear
collective excitations which have a finite lifetime on heavy-ion fusion
reactions at energies near and below the Coulomb barrier. Both spreading and
escape widths are explicitly taken into account in the exit doorway model. The
coupled-channels equations are numerically solved to show that the finite
resonance width always hinders fusion cross sections at subbarrier energies
irrespective of the relative importance between the spreading and the escape
widths. We also show that the structure of fusion barrier distribution is
smeared due to the spreading of the strength of the doorway state.Comment: 13 pages, 3 figures, Submitted to Physical Review
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