7,745 research outputs found
Do halos exist on the dripline of deformed nuclei?
A study of the effect of deformation and pairing on the development of halo
nuclei is presented. Exploratory three-body calculations show that
both the NN interaction and the deformation/excitation of the core hinder the
formation of the halo. Preliminary self-consistent mean-field calculations are
used to search for regions in the nuclear chart where halos could potentially
develop. These are also briefly discussed.Comment: 5 pages and 3 figures, proceedings for CGS1
Coupling and higher-order effects in the 12C(d,p)13C and 13C(p,d)12C reactions
Coupled channels calculations are performed for the 12C(d,p)13C and
13C(p,d)12C reactions between 7 and 60 MeV to study the effect of inelastic
couplings in transfer reactions. The effect of treating transfer beyond Born
approximation is also addressed. The coupling to the 12C 2+ state is found to
change the peak cross-section by up to 15 %. Effects beyond Born approximation
lead to a significant renormalization of the cross-sections, between 5 and 10 %
for deuteron energies above 10 MeV, and larger than 10 % for lower energies. We
also performed calculations including the remnant term in the transfer
operator, which has a small impact on the 12C(d,p)13C(g.s.) and
13C(p,d)12C(g.s.) reactions. Above 30 MeV deuteron energy, the effect of the
remnant term is larger than 10 % for the 12C(d,p)13C(3.09 MeV) reaction and is
found to increase with decreasing neutron separation energy for the 3.09 MeV
state of 13C. This is of importance for transfer reactions with weakly bound
nuclei.Comment: 7 pages, 7 figures, submitted to Phys. Rev.
Nonlinear dynamics of inhomogeneous mismatched charged particle beams
This work analyzes the transversal dynamics of an inhomogeneous and mismatched charged particle beam. The beam is azimuthally symmetric, initially cold, and evolves in a linear channel permeated by an external constant magnetic field. Based on a Lagrangian approach, a low-dimensional model for the description of the beam dynamics has been obtained. The small set of nonlinear dynamical equations provided results that are in reasonable agreement with that ones observed in full self-consistent N-particle beam numerical simulations
Nonlinear dynamics of relativistic charged particle beams
The idea behind this work is to analyze the transversal dynamics of a relativistic charged particle beam. The beam is azimuthally symmetric, focused by a constant magnetic field and supposed to be initially cold. While mismatched, nonrelativistic, and homogeneous beams oscillate with an invariant cold density profile, it is shown that relativistic homogeneous beams progressively heat and lose an important amount of constituents during its magnetic confinement. This heating process starts with phase-space wave-breaking, a mechanism observed before in initially inhomogeneous beams. The results have been obtained with full self-consistent N-particle beam numerical simulations
Brane Isotropisation in Extra-Dimensional Tolman-Bondi Universe
We consider the dynamics of a 3-brane embedded in an extra-dimensional
Tolman-Bondi Universe where the origin of space plays a special role. The
embedding is chosen such that the induced matter distribution on the brane
respects the spherical symmetry of matter in the extra dimensional space. The
mirage cosmology on the probe brane is studied, resulting in an inhomogeneous
and anisotropic four dimensional cosmology where the origin of space is also
special. We then focus on the spatial geometry around the origin and show that
the induced geometry, which is initially inhomogeneous and anisotropic,
converges to an isotropic and homogeneous Friedmann-Lemaitre 4d space-time. For
instance, when a 3-brane is embedded in a 5d matter dominated model, the 4d
dynamics around the origin converge to a Friedmann-Lemaitre Universe in a
radiation dominated epoch. We analyse this isotropisation process and show that
it is a late time attractor.Comment: 16 pages, 8 figures, one reference adde
Nuclear reaction studies of unstable nuclei using relativistic mean field formalisms in conjunction with Glauber model
We study nuclear reaction cross-sections for stable and unstable projectiles
and targets within Glauber model, using densities obtained from various
relativistic mean field formalisms. The calculated cross-sections are compared
with the experimental data in some specific cases. We also evaluate the
differential scattering cross-sections at several incident energies, and
observe that the results found from various densities are similar at smaller
scattering angles, whereas a systematic deviation is noticed at large angles.
In general, these results agree fairly well with the experimental data.Comment: 9 pages, 7 figures, submitted to PR
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