200 research outputs found
Three-body decays: structure, decay mechanism and fragment properties
We discuss the three-body decay mechanisms of many-body resonances. R-matrix
sequential description is compared with full Faddeev computation. The role of
the angular momentum and boson symmetries is also studied. As an illustration
we show the computed -particle energy distribution after the decay of
12C(1^+) resonance at 12.7 MeV.Comment: 4 pages, 3 figures. Proceedings of the workshop "Critical Stability
of Few-Body Quantum Systems" 200
Possibility to study a two-proton halo in Ne
The nuclide Ne is studied theoretically in a three-body
O++ model. We demonstrate that the experimental condition for
existence of a proton halo in Ne can be reasonably quantified in terms
of configuration mixing. We discuss experimental evidences for a proton
halo in Ne. We define which kind of experimental data could elucidate
this issue.Comment: 5 pages, 5 figure
Clustering in stable and unstable nuclei in -shell and -shell regions
According to microscopic calculations with antisymmetrized molecular
dynamics, we studied cluster features in stable and unstable nuclei. A variety
of structure was found in stable and unstable nuclei in the -shell and
-shell regions. The structure of excited states of Be was
investigated, while in -shell nuclei we focused on molecular states and
deformed states. The deformed states in Si and Ca were discussed
in connection with the high-lying molecular states. Appealing molecular states
in Ar and Mg were suggested. The results signified that both
clustering of nucleons and mean-field formation are essential features in
-shell nuclei as well as -shell nuclei.Comment: 5 pages, 2 figs, proceedings of the 8th International conference on
Clustering Aspects of Nuclear Structure and Dynamics, Nov. 2003, Nara, Japan,
to be published in Nucl.Phys.
Origin of Borromean systems
The complex energies of the three-body resonances for one infinitely heavy
particle and two non-interacting light particles are the sum of the two
contributing two-body complex resonance energies. The bound state of a
Borromean system originates from a resonance when the third interaction is
introduced, a finite mass is allowed and proper angular momentum coupling is
included. The relative importance of these contributions are investigated and
the resulting structure of Borromean systems are traced back to the two-body
continuum properties. The and states in He result from
neutron-core p-states and the ground and first excited state of Li
originate from neutron-core and -states.Comment: Physics Letters B, in pres
Dipole excited states in Li with complex scaling
The 1 excitations of the three--body halo nucleus Li are
investigated. We use adiabatic hyperspherical expansion and solve the Faddeev
equations in coordinate space. The method of complex scaling is used to compute
the resonance states. The Pauli forbidden states occupied by core neutrons are
excluded by constructing corresponding complex scaled phase equivalent two-body
potentials. We use a recently derived neutron--core interaction consistent with
known structure and reaction properties of Li and Li. The
computed dipole excited states with , , and
have energies ranging from 0.6 MeV to 1.0 MeV and widths between
0.15 MeV and 0.65 MeV. We investigate the dependence of the complex energies of
these states on the Li spectrum. The finite spin 3/2 of the core and the
resulting core-neutron spin-spin interaction are important. The connection with
Coulomb dissociation experiments is discussed and a need for better
measurements is pointed out.Comment: 28 pages, 6 figures, Nuclear Physics A, in pres
Inelastic scattering of protons from He and Li in a folding model approach
The proton-inelastic scattering from He and Li nuclei are
studied in a folding model approach. A finite-range, momentum, density and
isospin dependent nucleon-nucleon interaction (SBM) is folded with realistic
density distributions of the above nuclei. The renormalization factors N
and N on the real and volume imaginary part of the folded potentials are
obtained by analyzing the respective elastic scattering data and kept unaltered
for the inelastic analysis at the same energy. The form factors are generated
by taking derivatives of the folded potentials and therefore required
renormalizations. The values are extracted by fitting the p +
He,Li inelastic angular distributions. The present analysis of
p + He inelastic scattering to the 3.57 MeV excited state, including
unpublished forward angle data (RIKEN) confirms L = 2 transition. Similar
analysis of the p + He inelastic scattering angular distribution leading to
the 1.8 MeV (L = 2) excited state fails to satisfactorily reproduce the data.Comment: one LaTeX file, five PostScript figure
The Pauli principle in a three-body cluster model and the momentum distributions after fragmentation of 6He and 11Li
We investigate two simple prescriptions to account for the Pauli principle in
a three-body cluster model employing a new method based on an adiabatic
hyperspherical expansion to solve the Faddeev equations in coordinate space.
The resulting wave functions are computed and compared. They are furthermore
tested on halo nuclei by calculations of momentum distributions and invariant
mass spectra arising after fragmentation of fast He and Li in
collisions with light targets. The prescriptions are very accurate and the
available measured quantities are remarkably well reproduced when final state
interactions are included.Comment: 18 pages, LaTex file, 15 postscript figures included using epsf.st
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