Charmless hadronic decays B→VVB \to VV in the Topcolor-assisted Technicolor model

Based on the effective Hamiltonian with the generalized factorization approach, we calculate the branching ratios and CP asymmetries of $B \to VV$ decays in the Topcolor-assisted Technicolor (TC2) model. Within the considered parameter space we find that: (a) for the penguin-dominated $B \to K^{*+}\phi$ and $K^{*0}\phi$ decays, the new physics enhancements to the branching ratios are around 40%; (b) the measured branching ratios of $B \to K^{*+} \phi$ and $K^{*0} \phi$ decays prefer the range of 3 \lesssim \nceff \lesssim 5; (c) the SM and TC2 model predictions for the branching ratio ${\cal B}(B^+ \to \rho^+ \rho^0)$ are only about half of the Belle's measurement; and (d) for most $B \to VV$ decays, the new physics corrections on their CP asymmetries are generally small or moderate in magnitude and insensitive to the variation of \mpcc and \nceff.Comment: 16 pages, Revtex, 4 EPS figure

Rare decay B→XsννˉB \to X_{s} \nu \bar \nu in the two-Higgs-doublet model of type-III

In this paper, we calculated the new physics contribution to theoretically very clean rare decay $B\to X_{s} \nu \bar{\nu}$ in the general two-Higgs-doublet model (model III). Within the considered parameter space, we found that (a) the new physics contribution can provide one to two orders of enhancement to the branching ratio \calb(B\to X_s \nu \bar{\nu}) and can saturate the experimental bound on \calb(B \to X_s \nu \bar{\nu}) in some regions of the parameter space; (b) besides the CLEO data of $B \to X_s \gamma$, the ALEPH upper limit on \calb (B \to X_s \nu \bar{\nu}) also lead to further constraint on the size of the Yukawa coupling $\lambda_{tt}$: $\lambda_{tt}< 6.4$ for $\lambda_{bb}=2.7$ and \mhp=200 GeV.Comment: 10 pages, 3 figures in eps and 1 in ps, Latex fil

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.

Multiscale Technicolor and b→sγb \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.

The rare K-decays and Z0Z^0-penguin contributions in the Topcolor-assisted technicolor models

We calculate the new contributions to the rare decays $K^+ \to \pi^+ \nu \bar \nu$, $K_L \to \pi^0 \nu \bar \nu$ and $K_L \to \mu^+ \mu^-$ from new $Z^0$-penguin and box diagrams induced by the unit-charged scalars $(\tilde{\pi}^\pm, \tilde{H}^\pm, \pi_1^\pm, \pi_8^\pm)$ appeared in the Topcolor-assisted technicolor (TC2) models. We find that: (a) the unit-charged top-pion $\tilde{\pi}^\pm$ and b-pion $\tilde{H}^\pm$ can provide large contributions to the rare K-decays if they are relatively light; (b) the size of mixing elements $D_{L,R}^{ij}$ ($i \neq j$) is strongly constrained by the data of $B^0$ meson mixing: $|a_R^{ts}|, |a_R^{td}| < 0.01$ for $a_L^{td}=a_L^{ts}=1/2$ and $m_{\tilde{H}^0}\leq 600GeV$; (c) the enhancements to the branching ratios of rare K-decays from new scalars can be as large as one order of magnitude; (d) there is a strong cancellation between the short- and long-distance dispersive part of the decay $K_L \to \mu^+ \mu^-$, the constraint on the new short-distance part from this decay mode is thus not strong; (e) the typical TC2 model under study is generally consistent with the available rare K-decay data.Comment: Latex file, 27 pages and 10 ps and eps figures, to be published in Eur.Phys. J.

Technicolor corrections on Bs,d→γγB_{s,d} \to \gamma\gamma decays in QCD factorization

Within the framework of the Top-color-assisted Technicolor (TC2) model, we calculate the new physics contributions to the branching ratios \calb(B_{s,d} \to \gamma \gamma) and CP violating asymmetries \rcpm(B_{s,d} \to \gamma \gamma) in the QCD factorization based on the heavy-quark limit $m_b \gg \Lambda_{QCD}$. Using the considered parameter space, we find that (a) for both $B_s\to \gamma \gamma$ and $B_d \to \gamma \gamma$ decays, the new physics contribution can provide a factor of two to six enhancement to their branching ratios, (b) for the $B_s \to \gamma \gamma$ decay, its direct CP violation is very small in both the SM and TC2 model, and (c) the CP violating asymmetry \rcpm(B_d \to \gamma \gamma) is around the ten percent level in both the SM and TC2 model, but the sign of CP asymmetry in the TC2 model is different from that in the SM.Comment: 23 pages, Revtex, 9 PS/EPs figures, minor corrections, final version to appear in Phys.Rev.