65 research outputs found

### Multiscale Technicolor and $b \to s \gamma$

Correction to the $b\rightarrow s\gamma$ branching ratio in the multiscale
walking technicolor model (MWTCM) is examined. For the original MWTCM, the
correction is too large to explain the recent CLEO data. We show that if
topcolor is further introduced, the branching ratio in the topcolor assisted
MWTCM can be in agreement with the CLEO data for a certain range of the
parameters.Comment: 11 pages, Latex, no macros, 3 figures, hard copy is available upon
request. to appear in Z. Phys.

### Charmless decays B -> PP, PV, and effects of new strong and electroweak penguins in Topcolor-assisted Technicolor model

Based on the low energy effective Hamiltonian with generalized factorization,
we calculate the new physics contributions to the branching ratios and
CP-violating asymmetries of the two-body charmless hadronic decays $B \to PP,
PV$ from the new strong and electroweak penguin diagrams in the TC2 model. The
top-pion penguins dominate the new physics corrections, and both new gluonic
and electroweak penguins contribute effectively to most decay modes. For
tree-dominated decay modes $B \to \pi \pi, \rho \pi, etc,$ the new physics
corrections are less than 10%. For decays $B \to K^{(*)} \pi$, $K^{(*)} \eta$,
$etc$, the new physics enhancements can be rather large (from $- 70%$ to $\sim
200%$) and are insensitive to the variations of $N_c^{eff}$, $k^2$, $\eta$ and
$m_{\tilde{\pi}}$ within the reasonable ranges. For decays $B^0 \to \phi \pi$,
$\phi \eta^{(')}$, $K^* \bar{K}^0$ and $\rho^+ K^0$, $\delta {\cal B}$ is
strongly $N_c^{eff}-$dependent: varying from -90% to $\sim 1680%$ in the range
of $N_c^{eff}=2-\infty$. The new physics corrections to the CP-violating
asymmetries ${\cal A}_{CP}$ vary greatly for different B decay channels. For
five measured CP asymmetries of $B \to K \pi, K \eta', \omega \pi$ decays,
$\delta {\cal A}_{CP}$ is only about 20% and will be masked by large
theoretical uncertainties. The new physics enhancements to interesting $B \to K
\eta'$ decays are significant in size ($\sim 50%$), insensitive to the
variations of input parameters and hence lead to a plausible interpretation for
the unexpectedly large $B \to K \eta'$ decay rates. The TC2 model predictions
for branching ratios and CP-violating asymmteries of all fifty seven $B \to PP,
PV$ decay modes are consistent with the available data within one or two
standard deviations.Comment: Latex file, 56 pages with 11 ps and eps figures. to be published in
Eur.Phys.J.

### The ${\Upsilon}(nS)$ ${\to}$ $B_{c}^{\ast}{\pi}$, $B_{c}^{\ast}K$ decays with perturbative QCD approach

Besides the traditional strong and electromagnetic decay modes,
${\Upsilon}(nS)$ meson can also decay through the weak interactions within the
standard model of elementary particle. With anticipation of copious
${\Upsilon}(nS)$ data samples at the running LHC and coming SuperKEKB
experiments, the two-body nonleptonic bottom-changing ${\Upsilon}(nS)$ ${\to}$
$B_{c}^{\ast}{\pi}$, $B_{c}^{\ast}K$ decays ($n$ $=$ 1, 2, 3) are investigated
with perturbative QCD approach firstly. The absolute branching ratios for
${\Upsilon}(nS)$ ${\to}$ $B_{c}^{\ast}{\pi}$ and $B_{c}^{\ast}K$ decays are
estimated to reach up to about $10^{-10}$ and $10^{-11}$, respectively, which
might possibly be measured by the future experiments.Comment: 16 pages, 3 figure

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