625 research outputs found
Stent-grafting for a thoracic aortic aneurysm ruptured into the right pleural cavity
AbstractEur J Vasc Endovasc Surg 25, 185–187 (2003
Role of electromagnetic dipole operator in the electroweak penguin dominated vector meson decays of meson
The pure annihilation type decays and
receive only color suppressed penguin contributions with a very small branching
ratio in the standard model. When we include the previously neglected
electromagnetic dipole operator, the branching ratios can be enhanced one order
magnitude larger than previous study using QCD factorization approach. That is
and . The new effect can also give
a large contribution, of order , to transverse polarization of
and which is comparable to the longitudinal
part. These effects can be detected in the LHCb experiment and the Super-B
factories.Comment: Revised extensively. 8 pages, 4 figure
Study of color suppressed modes
The color suppressed modes are
analyzed in perturbative QCD approach. We find that the dominant contribution
is from the non-factorizable diagrams. The branching ratios calculated in our
approach for agree with current experiments. By
neglecting the gluonic contribution, we predict the branching ratios of are at the comparable size of , but smaller than that of .Comment: revtex, 5 pages, axodraw.st
Study of decays
We investigate the production of the novel -wave mesons and
, identified as and , in heavy
meson decays, respectively. With the heavy quark limit, we give our modelling
wave functions for the scalar meson . Based on the assumptions of
color transparency and factorization theorem, we estimate the branching ratios
of decays in terms of the obtained wave functions. Some
remarks on productions are also presented.Comment: 16 pages, 2 figures, Revtex4, to be published in Phys. Rev.
Evolution of the streamwise vortices in a coaxial jet controlled with micro flap-actuators
A coaxial jet was actively controlled by a MEMS-fabricated micro flap actuator nozzle. The effect of different control modes on secondary azimuthal instabilities and the evolution of streamwise vortices were investigated by applying stereoscopic PIV to the cross-stream plane of the jet. Forcing with non-symmetric modes, in particular the least-stable helical mode, accelerates the evolution of the streamwise vortices through the enhancement of azimuthal instabilities. Although forcing is applied to the outer shear layer of the outer jet, the control effect is most pronounced in the inner shear layer of the inner jet. Unlike in the natural jet, streamwise vortices appear in the inner shear layer of the controlled jet. For forcing with the fundamental axisymmetric mode, a Strouhal number of the order of unity maximise the azimuthal instabilities and hence the counts of the streamwise vortices. The present result is in accordance with our previous experimental findings in the longitudinal plane, where the evolution of the primary vortices and mixing between the inner and the outer jets were examined through 2D-PIV and PLI
Branching ratios of decays in perturbative QCD approach
We study the rare decays , which can occur only via
annihilation type diagrams in the standard model. We calculate all of the four
modes, , in the framework of perturbative QCD approach
and give the branching ratios of the order about .Comment: 18 pages, 1 figure, Revte
Possible Large Direct CP Violations in Charmless B-Decays
We discuss the perturbative QCD approach for the exclusive two body B-meson
decays to light mesons. We briefly review its ingredients and some important
theoretical issues on factorization approach. We show numerical results which
are compatible with present experimantal data for the charmless B-meson decays.
Specailly we predict the possibility of large direct CP violation effects in
and .
In the last section we investigate two methods to determine the weak phases
and from processes. We obtain bounds on
and from present experimental measurements.Comment: 18 pages, latex, 8 figures and 8 tables, typos corrected and added
more tables and references. Presented at the 3rd workshop on Higher
Luminosity B Factory, 6-7 August 2002, Kanagawa, Japan; Submitted to Phys.
Rev.
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