4,315 research outputs found
Calculation of the Branching Ratio of in PQCD
The branching ratio of is re-evaluated in the PQCD approach.
In this theoretical framework all the phenomenological parameters in the
wavefunctions and Sudakov factor are priori fixed by fitting other experimental
data, and in the whole numerical computations we do not introduce any new
parameter. Our results are consistent with the upper bounds set by the Babar
and Belle measurements.Comment: 12 pages, 1 figure, version to appear in Phys. Rev.
Effects of Geometrical Symmetry on the Vortex Nucleation and Penetration in Mesoscopic Superconductors
We investigate how the geometrical symmetry affects the penetration and
arrangement of vortices in mesoscopic superconductors using self-consistent
Bogoliubov-de Gennes equations. We find that the entrance of the vortex happens
when the current density at the hot spots reaches the depairing current
density. Through determining the spatial distribution of hot spots, the
geometrical symmetry of the superconducting sample influences the nucleation
and entrance of vortices. Our results propose one possible experimental
approach to control and manipulate the quantum states of mesoscopic
superconductors with their topological geometries, and they can be easily
generalized to the confined superfluids and Bose-Einstein condensates
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