35 research outputs found
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
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
Toroidal quadrupole transitions associated to collective rotational-vibrational motions of the nucleus
In the frame of the algebraic Riemann Rotational Model one computes the
longitudinal, transverse and toroidal multipoles corresponding to the
excitations of low-lying levels in the ground state band of several even-even
nuclei by inelastic electron scattering (e,e'). Related to these transitions a
new quantity, which accounts for the deviations from the Siegert theorem, is
introduced. The intimate connection between the nuclear vorticity and the
dynamic toroidal quadrupole moment is underlined. Inelastic differential
cross-sections calculated at backscattering angles shows the dominancy of
toroidal form-factors over a broad range of momentum transfer.Comment: 11 pages in LaTex, 3 figures available by fax or mail, accepted for
publication in J.Phys.
Peculiarities of sub-barrier fusion with quantum diffusion approach
With the quantum diffusion approach the unexpected behavior of fusion cross
section, angular momentum, and astrophysical S-factor at sub-barrier energies
has been revealed. Out of the region of short-range nuclear interaction and
action of friction at turning point the decrease rate of the cross section
under the barrier becomes smaller. The calculated results for the reactions
with spherical nuclei are in a good agreement with the existing experimental
data.Comment: 11 pages, 5 figure
The systematic study of the influence of neutron excess on the fusion cross sections using different proximity-type potentials
Using different types of proximity potentials, we have examined the trend of
variations of barrier characteristics (barrier height and its position) as well
as fusion cross sections for 50 isotopic systems including various collisions
of C, O, Mg, Si, S, Ca, Ar, Ti and Ni nuclei with condition
for compound systems. The results of our studies reveal that the relationships
between increase of barrier positions and decrease of barrier heights are both
linear with increase of ratio. Moreover, fusion cross sections also
enhance linearly with increase of this ratio.Comment: 28 pages, 7 figures, 5 Table
Sub-barrier capture with quantum diffusion approach: actinide-based reactions
With the quantum diffusion approach the behavior of capture cross sections
and mean-square angular momenta of captured systems are revealed in the
reactions with deformed nuclei at subbarrier energies. The calculated results
are in a good agreement with existing experimental data. With decreasing
bombarding energy under the barrier the external turning point of the
nucleusnucleus potential leaves the region of short-range nuclear interaction
and action of friction. Because of this change of the regime of interaction, an
unexpected enhancement of the capture cross section is expected at bombarding
energies far below the Coulomb barrier. This effect is shown its worth in the
dependence of mean-square angular momentum of captured system on the bombarding
energy. From the comparison of calculated and experimental capture cross
sections, the importance of quasifission near the entrance channel is shown for
the actinide-based reactions leading to superheavy nuclei.Comment: 11 pages, 16 figures, Regular Articl
Multipolar model of bremsstrahlung accompanying proton-decay of nuclei
Emission of bremsstrahlung photons accompanying proton decay of nuclei is
studied. The new improved multipolar model describing such a process is
presented. The angular formalism of calculations of the matrix elements is
stated in details. The bremsstrahlung probabilities for the ,
, and nuclei decaying from
the state, the and nuclei decaying from the state, the and nuclei decaying from the
state are predicted. Such spectra have orders of values similar to the
experimental data for the bremsstrahlung photons emitted during the
-decay. This indicates on real possibility to study bremsstrahlung
photons during proton decay experimentally and perform further measurements.Comment: 14 pages, 6 figure