9 research outputs found
Analysis of the Rare Decays in QCD
The rare decays are investigated in the
framework of the three point QCD sum rules approach. Considering the gluon
condensate corrections to the correlation function, the form factors relevant
to these transitions are calculated. The total decay width and branching ratio
for these decays are also evaluated. The results for the branching ratios are
in good agreement with the quark models.Comment: 20 Pages, 2 Figures and 5 Table
Investigation of the structure via to transitions in QCD
We investigate the structure of the mesons via
analyzing the semileptonic , and
transitions in the framework of the three--point
QCD sum rules. We consider the meson in two ways, the pure
state and then as a mixture of two and states.
Such type rare transitions take place at loop level by electroweak penguin and
weak box diagrams in the standard model via the flavor changing neutral current
transition of . The relevant form factors are calculated taking into
account the gluon condensate contributions. These form factors are numerically
obtained for case and plotted in terms of the unknown mixing angle
, when the meson are considered as mixture of two
and states. The obtained results for the form factors are used to
evaluate the decay rates and branching ratios. Any future experimental
measurement on these form factors as well as decay rates and branching
fractions and their comparison with the obtained results in the present work
can give considerable information about the structure of this meson and the
mixing angle .Comment: 33 Pages, 11 Figures and 5 Table
The Effects of Fourth Generation on the double Lepton Polarization in B \rar K \ell^+ \ell^- decay
This study investigates the influence of the fourth generation quarks on the
double lepton polarizations in B \rar K \ell^+ \ell^- decay. Taking
|V_{t's}V_{t'b}|\sim \{0.01-0.03\} with phase about 100^\circ, which is
consistent with the b\to s\ell^+\ell^- rate and the B_s mixing parameter Delta
m_{B_s}$, we obtain that the double lepton(muon and tau) polarizations are
quite sensitive to the existence of fourth generation. It can serve as a good
tool to search for new physics effects, precisely, to indirect search for the
fourth generation quarks(t', b').Comment: 30 pages, 27 figure