4,878 research outputs found
Nuclear Tetrahedral Symmetry
We recall the main features of the Td (tetrahedral) symmetry in atomic nuclei
and present realistic mean-field calculations supporting the existence such a
symmetry all over the nuclear chart. A few potential candidate-nuclei are
investigated and the possible experimental signatures of the tetrahedral
symmetry are also briefly discussed.Comment: Proceedings of the Xth Marie Curie Nuclear Theory Workshop, Kazimierz
Dolny, Poland 4 pages, 1 figur
Collective Rotation of Tetrahedral Nuclei in the Cranking Model
The three-dimensional cranking model is used to investigate the microscopic
aspects of the rotation of nuclei with the tetrahedral symmetry. Two classes of
rotation axes are studied corresponding to two different discrete symmetries of
the rotating hamiltonian. Self-consistent Hartree-Fock-Bogoliubov calculations
show that the tetrahedral minimum remains remarkably stable until the first
single-particle crossing.Comment: Proceedings of the XII Nuclear Physics Workshop Pierre and Marie
Curie, October 2005. To be published in IJMP
Nuclei with Tetrahedral Symmetry
We discuss a point-group-theory based method of searching for new regions of
nuclear stability. We illustrate the related strategy with realistic
calculations employing the tetrahedral and the octahedral point groups. In
particular, several nuclei in the Rare Earth region appear as excellent
candidates to study the new mechanism.Comment: 18 pages, 4 figures, submitted to International Journal of Modern
Physics
Nuclear Liquid Drop Model with the Surface-Curvature Terms: New Perspectives for the Hyperdeformation Studies
Nuclear liquid drop model is revisited and an explicit introduction of the
surface-curvature terms is presented. The corresponding parameters of the
extended classical energy formula are adjusted to the contemporarily known
nuclear binding energies and fission barrier heights. Using 2766 binding
energies of nuclei with and it is shown that the
performance of the new approach is improved by a factor of about 6, compared to
the previously published liquid drop model results, in terms of both the masses
(new r.m.s. deviation MeV) and the fission barriers (new
r.m.s. deviation of the fission barriers of isotopes with is MeV).
The role of the curvature terms and their effects on the description of the
experimental quantities are discussed in detail; for comparison the parameters
of the more 'traditional' approaches are re-fitted taking into account the
nuclear masses known today and the performances of several variants of the
model are compared. The isospin dependence in the new description of the
barriers is in a good agreement with the extended Thomas-Fermi approach; it
also demonstrates a good qualitative agreement with the fission life-time
systematics tested on the long chain of Fermium isotopes known experimentally.
The new approach offers also a very high stability in terms of the
extrapolation from the narrower range of nuclides to a more extended one - a
property of particular interest for the contemporary exotic beam projects: the
corresponding properties are illustrated and discussed.Comment: 25 pages in LaTeX and 20 figures in eps forma
Hybrid meson production by electromagnetic and weak interactions in a flux-tube simulation of lattice QCD
We calculate rates for hybrid meson production by electromagnetic and weak
interactions in the flux-tube model. Applications include photo and
electroproduction at Jefferson Laboratory and HERA, and the production of light
strange and charmed hybrids in the weak decays of heavy flavours.
Photoproduction of some light hybrids is predicted to be prominent in charge
exchange reactions, and accessible in . Production of light or charmed hybrids in and decays may be
feasible with high statistics. Photoproduction of the axial hybrid meson is
predicted to be large courtesy of exchange, and its strange counterpart
is predicted in with . Production
rates for exotic hybrid candidates are given special
attention. Selection rules that can help to distinguish between hybrid and
conventional states with the same are noted.Comment: uses psfrag; One reference correcte
HFODD (v2.08k): User's Guide
We describe the input data and installation procedures of the code HFODD
(v2.08k). The present write-up contains complete and comprehensive information
that has originally been given in five independent publications. It is enhanced
by the subject index and indexes of variables, input-data keywords,
subroutines, and files that are used in this user guide.Comment: 100 LaTeX pages, 1 EPS figure, Table 7 corrected, on-line-only
publication, see also http://www.fuw.edu.pl/~dobaczew/hfodd/hfodd.htm
Search for the Skyrme-Hartree-Fock Solutions for Chiral Rotation in N=75 Isotones
A search for the self-consistent solutions for the chiral rotational bands in
the N=75 isotones, 130Cs, 132La, 134Pr and 136Pm is performed within the
Skyrme-Hartree-Fock cranking approach using SKM* and SLy4 parametrizations. The
dependence of the solutions on the time-odd contributions in the energy
functional is studied. From among the considered four isotones, self-consistent
chiral solutions are obtained only in 132La. The microscopic calculations are
compared with the 132La experimental data and with results of a classical model
that contains all the mechanisms underlying the chirality of the collective
rotational motion. Strong similarities between the HF and classical model
results are found. The suggestion formulated earlier by the authors that the
chiral rotation cannot exist below a certain critical frequency is further
illustrated and discussed, together with the microscopic origin of a transition
from the planar to chiral rotation in nuclei. We also formulate the
separability rule by which the Tilted-Axis-Cranking solutions can be inferred
from three independent Principal-Axis-Cranking solutions corresponding to three
different axes of rotation.Comment: 23 LaTeX pages, 11 PostScript Figure
Electroweak production of hybrid mesons in a Flux-Tube simulation of Lattice QCD
We make the first calculation of the electroweak couplings of hybrid mesons
to conventional mesons appropriate to photoproduction and to the decays of
or mesons. amplitudes are found to be large and may contribute in
charge exchange allowing production of (amongst others)
the charged exotic hybrid off exchange. Axial hybrid meson
photoproduction is predicted to be large courtesy of exchange, and its
strange hybrid counterpart is predicted in with . Higher multipoles, and some implications for hybrid charmonium
are briefly discussed.Comment: 4 page
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