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Particles and Fields


Eur. Phys. J. C 18, 681-709
DOI: 10.1007/s100520100562

Charmless decays $B \to {\mathrm {PP}}, {\mathrm {PV}}$, and the effects of new strong and electroweak penguins in topcolor-assisted technicolor model

Z.J. Xiao1, 2, 3, W.J. Li2, L.B. Guo1, 4 and G.R. Lu1, 2

1  CCAST(World Laboratory) P.O. Box 8730, Beijing 100080, P.R. China
2  Department of Physics, Henan Normal University, Xinxiang 453002, P.R. China
3  Department of Physics, Peking University, Beijing 100871, P.R. China
4  Department of Physics, Wuhan University, Wuhan 430000, P.R. China

(Received: 18 August 2000 / Revised version: 22 October 2000 / Published online: 5 February 2001 -© Springer-Verlag 2001)

Abstract
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 $B \to {\mathrm {PP}}, {\mathrm {PV}}$ from the new strong and electroweak penguin diagrams in the topcolor-assisted technicolor (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 $, $\pi^0 \eta^{('
)}$, $\eta^{(')}\eta^{(')}$, $K \overline{K}^0$, $\overline{K}^{*0}
K$, etc. the new physics enhancements can be rather large (from $- 70\%$ to $ \sim
200\%$) and are insensitive to the variations of Nceff, k2, $\eta$ and $m_{\tilde{\pi}}$ within reasonable ranges. For the decays $B^0 \to \phi \pi$, $\phi \eta^{(')}$, $K^*
\overline{K}^0$ and $\rho^+ K^0$, $
\delta {\cal B}$ is strongly Nceff dependent: varying from $-90\%$ to $\sim 1680\%$ in the range of Nceff=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 the $B \to K \pi, K \eta^{\prime}, \omega \pi$ decays, $
\delta {\cal A}_{CP}$ is only about $20\%$ and will be masked by large theoretical uncertainties. The new physics enhancements to interesting $B \to K \eta^{\prime}$ decays are significant in size ($\sim 50\%$), insensitive to the variations of the input parameters and hence lead to a plausible interpretation for the unexpectedly large $B \to K \eta^{\prime}$ decay rates. The TC2 model predictions for branching ratios and CP-violating asymmteries of all fifty-seven $B \to {\mathrm {PP, PV}}$ decay modes are consistent with the available data within one or two standard deviations.



© Società Italiana di Fisica, Springer-Verlag 2001