60 research outputs found
Nuclear Deformation Effects in the Cluster Radioactivity
We investigate the influence of the nuclear deformation on the decay rates of
some cluster emission processes. The interaction between the daughter and the
cluster is given by a double folding potential including quadrupole and
hexadecupole deformed densities of both fragments. The nuclear part of the
nucleus-nucleus interaction is density dependent and at small distances a
repulsive core in the potential will occur. In the frame of the
WKB-approximation the assault frequency of the cluster will depend on the
geometric properties of the potential pocket whereas the penetrability will be
sensitive to changes in the barrier location. The results obtained in this
paper point out that various combinations of cluster and daughter deformations
may account for the measured values of the decay rate.T he decay rather are
however more sensitive to the changes in the daughter deformation due to the
large mass asymmetry of the process.Comment: 11 pages, 6 figure
Dual Killing-Yano symmetry and multipole moments in electromagnetism and mechanics of continua
In this work we introduce the Killing-Yano symmetry on the phase space and we
investigate the symplectic structure on the space of Killing-Yano tensors. We
perform the detailed analyze of the -dimensional flat space and the
Riemaniann manifolds with constant scalar curvature. We investigate the form of
some multipole tensors, which arise in the expansion of a system of charges and
currents, in terms of second-order Killing-Yano tensors in the phase space of
classical mechanics.
We find some relations between these tensors and the generators of dynamical
symmetries like the angular momentum, the mass-inertia tensor, the conformal
operator and the momentum conjugate Runge-Lenz vector.Comment: 11 pages LaTeX, no figures, content enlarged and revised, accepted
for publication in Helvetica Physica Act
Cluster Expansion of Cold Alpha Matter Energy
In the cluster expansion framework of Bose liquids we calculate analytical
expressions of the two-body, three-body and four-body diagrams contributing to
the g.s. energy of an infinite system of neutral alpha-particles at
zero-temperature, interacting via the strong nuclear forces exclusively. This
is analytically tractable by assuming a density dependent two-body correlation
function of Gaussian type. For the alpha-alpha potential we adopt the
phenomenological Ali-Bodmer interaction and semi-microscopic potentials
obtained from the Gogny force parametrizations. We show that under such
assumptions we achieve a rapid convergence in the cluster expansion, the
four-body contributions to the energy being smaller than the two-body and
three-body contributions by at least an order of magnitude.Comment: 22 pages, 13 figure
Proton Decay from Excited States in Spherical Nuclei
Based on a single particle model which describes the time evolution of the
wave function during tunneling across a one dimensional potential barrier we
study the proton decay of Pb from excited states with non-vanishing
angular momentum . Several quantities of interest in this process like
the decay rate , the period of oscillation , the transient
time , the tunneling time and the average value of the proton
packet position are computed and compared with the WKB results.Comment: 12 pages, 4 figure
Collective Modes of Tri-Nuclear Molecules
A geometrical model for tri-nuclear molecules is presented. An analytical
solution is obtained provided the nuclei, which are taken to be prolately
deformed, are connected in line to each other. Furthermore, the tri-nuclear
molecule is composed of two heavy and one light cluster, the later sandwiched
between the two heavy clusters. A basis is constructed in which Hamiltonians of
more general configurations can be diagonalized. In the calculation of the
interaction between the clusters higher multipole deformations are taken into
account, including the hexadecupole one. A repulsive nuclear core is introduced
in the potential in order to insure a quasi-stable configuration of the system.
The model is applied to three nuclear molecules, namely Sr + Be +
Ba, Mo + Be + Te and Ru + Be +
Sn.Comment: 24 pages, 9 figure
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