716 research outputs found
One- and two-proton transfer reactions with vibrational Nuclei
We extend a semiclassical model of transfer reactions to the case in which
one of the collision partners is a vibrational nucleus. The model is applied to
one- and two-proton stripping reactions in the 37Cl + 98Mo system, for which a
rapid transition from normal to anomalous slope in the two proton transfer
reaction at energies around the Coulomb barrier is experimentally observed.
This behavior is satisfactorily reproduced by the present extension of the
model.Comment: LaTeX, 10 pages, 1 figure (PostScript
Dynamical Evolution of Boson Stars II: Excited States and Self-Interacting Fields
The dynamical evolution of self-gravitating scalar field configurations in
numerical relativity is studied. The previous analysis on ground state boson
stars of non-interacting fields is extended to excited states and to fields
with self couplings.
Self couplings can significantly change the physical dimensions of boson
stars, making them much more astrophysically interesting (e.g., having mass of
order 0.1 solar mass). The stable () and unstable () branches of
equilibrium configurations of boson stars of self-interacting fields are
studied; their behavior under perturbations and their quasi-normal oscillation
frequencies are determined and compared to the non-interacting case.
Excited states of boson stars with and without self-couplings are studied and
compared. Excited states also have equilibrium configurations with and
branch structures; both branches are intrinsically unstable under a generic
perturbation but have very different instability time scales. We carried out a
detailed study of the instability time scales of these configurations. It is
found that highly excited states spontaneously decay through a cascade of
intermediate states similar to atomic transitions.Comment: 16 pages+ 13 figures . All figures are available at
http://wugrav.wustl.edu/Paper
Role of Present and Future Atomic Parity Violation Experiments in Precision Electroweak Tests
Recent reanalyses of the atomic physics effects on the weak charge in cesium
have led to a value in much closer agreement with predictions of the Standard
Model. We review precision electroweak tests, their implications for upper
bounds on the mass of the Higgs boson, possible ways in which these bounds may
be circumvented, and the requirements placed upon accuracy of future atomic
parity violation experiments by these considerations.Comment: 10 pages, LaTeX, 1 figure, to be submitted to Physical Review D, new
data on neutrino deep inelastic scattering include
Finite element approximation of the -Laplacian
We study a~priori estimates for the Dirichlet problem of the
-Laplacian,
We show that the gradients of the finite element approximation with zero
boundary data converges with rate if the exponent is
-H\"{o}lder continuous. The error of the gradients is measured in the
so-called quasi-norm, i.e. we measure the -error of
On the evaluation of some three-body variational integrals
Stable recursive relations are presented for the numerical computation of the
integrals
(, and integer, , and real) when the
indices , or are negative. Useful formulas are given for particular
values of the parameters , and .Comment: 12 pages, 1 figure (PS) and 3 tables. Old figures 2 and 3 replaced by
Tables I and III. A further table added. Paper enlarged giving some tips on
the convergence of quadrature
Evaluation of the self-energy correction to the g-factor of S states in H-like ions
A detailed description of the numerical procedure is presented for the
evaluation of the one-loop self-energy correction to the -factor of an
electron in the and states in H-like ions to all orders in .Comment: Final version, December 30, 200
2s Hyperfine Structure in Hydrogen Atom and Helium-3 Ion
The usefulness of study of hyperfine splitting in the hydrogen atom is
limited on a level of 10 ppm by our knowledge of the proton structure. One way
to go beyond 10 ppm is to study a specific difference of the hyperfine
structure intervals 8 Delta nu_2 - Delta nu_1. Nuclear effects for are not
important this difference and it is of use to study higher-order QED
corrections.Comment: 10 pages, presented at Hydrogen Atom II meeting (2000
Long Range Magnetic Order and the Darwin Lagrangian
We simulate a finite system of confined electrons with inclusion of the
Darwin magnetic interaction in two- and three-dimensions. The lowest energy
states are located using the steepest descent quenching adapted for velocity
dependent potentials. Below a critical density the ground state is a static
Wigner lattice. For supercritical density the ground state has a non-zero
kinetic energy. The critical density decreases with for exponential
confinement but not for harmonic confinement. The lowest energy state also
depends on the confinement and dimension: an antiferromagnetic cluster forms
for harmonic confinement in two dimensions.Comment: 5 figure
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