7,185 research outputs found
A Semiclassical Approach to Fusion Reactions
The semiclassical method of Alder and Winther is generalized to study fusion
reactions. As an illustration, we evaluate the fusion cross section in a
schematic two-channel calculation. The results are shown to be in good
agreement with those obtained with a quantal Coupled-Channels calculation. We
suggest that in the case of coupling to continuum states this approach may
provide a simpler alternative to the Continuum Discretized Coupled-Channels
method.Comment: 6 pages, 1 figure, invited talk at the International Symposium "A new
era of Nuclear Structure Physics", Niigata, Japan, Nov. 19-22 200
Transverse Isotropy in Identical Particle Scattering
It is pointed out that the cross section for the scattering of identical
charged bosons is isotropic over a broad angular range around 90 degrees when
the Sommerfeld parameter has a critical value, which depends exclusively on the
spin of the particle. A discussion of systems where this phenomenon can be
observed is presented.Comment: 8 pages, RevTeX format, 2 figures (.eps format
A study of local approximation for polarization potentials
We discuss the derivation of an equivalent \textit{l}-independent
polarization potential for use in the optical Schr\"{o}dinger equation that
describes the elastic scattering of heavy ions. Three diffferent methods are
used for this purpose. Application of our theory to the low energy scattering
of the halo nucleus Li from a C target is made. It is found that
the notion of \textit{l}-independent polarization potential has some validity
but can not be a good substitute for the \textit{l}-dependent local equivalent
Feshbach polarization potential.Comment: 8 pages, 4 figure
Analytic Simulations of Packaging Cardboards with Non-Rigid Adhesives
The understanding of the cardboard performance is necessary to the design of packaging containers and the protection of their contents for safe deliveries. The use of adhesives is unavoidable in the manufacturing of the cardboards. Like all materials, the adhesives have finite stiffness but when used in the literature, they are assumed perfectly rigid. This study changes this assumption by using the real properties of adhesives. A closed-form solution for cardboard panelsassembled withnon-rigid adhesives, and subjected to edgewise loading is presented. The solution satisfies the equilibrium equations of the layers, the compatibility equations of stresses and strains at the interfaces, and the boundary conditions. To investigate the effects of the finite values of adhesivestiffness on the responses, numerical evaluations are conducted. The results obtained have shown that the adhesive stiffness has a strong effect on the performance. Beyond a certain level of stiffness, the usual assumption of perfect bonding used in classical theories is acceptable. This could provide an answer to what constitutes perfect bonding in terms of the ratio of the fluted layer, or simply flute, stiffness to the bonding stiffness
Geometry of Borromean Halo Nuclei
We discuss the geometry of the highly quantal nuclear three-body systems
composed of a core plus two loosely bound particles. These Borromean nuclei
have no single bound two-body subsystem. Correlation plays a prominent role.
From consideration of the value extracted from electromagnetic
dissociation, in conjunction with HBT-type analysis of the two valence-halo
particles correlation, we show that an estimate of the over-all geometry can be
deduced. In particular we find that the opening angle between the two neutrons
in He and Li are, respectively, and . These angles are
reduced by about 12% to and
if the laser spectroscopy values of the rms charge
radii are used to obtain the rms distance between the cores and the center of
mass of the two neutrons. The opening angle in the case of Li is more
than 20% larger than recently reported by Nakamura \cite{Nak06}. The analysis
is extended to Be and the two-proton Borromean nucleus Ne where
complete data is still not available. Using available experimental data and
recent theoretical calculations we find,
and , respectively.Comment: 5 pages, one figure, version to appear in PRC, Rapid Communication
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