113,144 research outputs found
Microscopic analysis of K^+-nucleus elastic scattering based on K^+N phase shifts
We investigate -nucleus elastic scattering at intermediate energies
within a microscopic optical model approach. To this effect we use the current
-nucleon {\it (KN)} phase shifts from the Center for Nuclear Studies of
the George Washington University as primary input. First, the {\it KN} phase
shifts are used to generate Gel'fand-Levitan-Marchenko real and local inversion
potentials. Secondly, these potentials are supplemented with a short range
complex separable term in such a way that the corresponding unitary and
non-unitary {\it KN} matrices are exactly reproduced. These {\it KN}
potentials allow to calculate all needed on- and off-shell contributions of the
matrix,the driving effective interaction in the full-folding
-nucleus optical model potentials reported here. Elastic scattering of
positive kaons from Li, C, Si and Ca are studied at
beam momenta in the range 400-1000 MeV/{}, leading to a fair description of
most differential and total cross section data. To complete the analysis the
full-folding model, three kinds of simpler calculations are considered
and results discussed. We conclude that conventional medium effects, in
conjunction with a proper representation of the basic {\it KN} interaction are
essential for the description of -nucleus phenomena.Comment: 11 pages, 1 table, 12 figures, submitted to PR
Interference of multiplane wings having elliptical lift distribution
In calculating the self-induction of a wing surface, elliptical lift distribution is assumed, while in calculating the mutual induction or interference of two wing surfaces, a uniform distribution of the lift along the wing has hitherto been assumed. Whether the results of these calculations are substantially altered by assuming an elliptical lift distribution (which is just as probable as uniform distribution) is examined here
Spectrum and Dynamics of the BCS-BEC crossover from a few-body perspective
The spectrum of two spin-up and two spin-down fermions in a trap is
calculated using a correlated gaussian basis throughout the range of the
BCS-BEC crossover. These accurate calculations provide a few-body solution to
the crossover problem. This solution is used to study the time-evolution of the
system as the scattering length is changed, mimicking experiments with Fermi
gases near Fano-Feshbach resonances. The structure of avoiding crossings in the
spectrum allow us to understand the dynamics of the system as a sequence of
Landau-Zener transitions. Finally, we propose a ramping scheme to study
atom-molecule coherence.Comment: 4 pages, final version to appear in PR
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