Yukawa Corrections to gamma gamma --> b\bar{b} in the Topcolor Assisted Technicolor Models

We study the Yukawa corrections to the gamma gamma --> b\bar{b} corss section in the topcolor assisted technicolor models at the photon-photon colliders. We find that, for the favorable parameters, the relative corrections from pseudo Goldstone bosons give out a 3.2%--5.9% decrement of the cross section from the tree level when \sqrt{s}=500 GeV, the contributions from new extended technicolor gauge bosons Z* and colored gauge bosons B are negligibly small, and the relative correction arising from new color-singlet heavy gauge boson Z' is less than -3.2%. Therefore, the total relative corrections are significantly larger than the corresponding corrections in the standard model, the general two Higgs doublet model and the minimal supersymmetric standard model. Since these corrections are obvious for the International Linear Colliders, the process gamma gamma --> b\bar{b} is really interesting in testing the standard model and searching for the signs of technicolor.Comment: 24 pages, 6 figures, version appeared in PR

Study of the ψ(1S,2S){\psi}(1S,2S) and ηc(1S,2S){\eta}_{c}(1S,2S) weak decays into DMDM

Inspired by the recent measurements on the $J/{\psi}(1S)$ ${\to}$ $D_{s}{\rho}$, $D_{u}K^{\ast}$ weak decays at BESIII and the potential prospects of the charmonium at the high-luminosity heavy-flavor experiments, we study ${\psi}(1S,2S)$ and ${\eta}_{c}(1S,2S)$ weak decays into final states including one charmed meson plus one light meson, considering the QCD corrections to hadronic matrix elements with the QCD factorization. It is found that the Cabibbo favored ${\psi}(1S,2S)$ ${\to}$ $D_{s}^{-}{\rho}^{+}$, $D_{s}^{-}{\pi}^{+}$, $\overline{D}_{u}^{0}\overline{K}^{{\ast}0}$ decays have branching ratios ${\gtrsim}$ $10^{-10}$, which might be accessible at the future experiments.Comment: 20 pages, revte

The Υ(nS){\Upsilon}(nS) →{\to} Bc∗πB_{c}^{\ast}{\pi}, Bc∗KB_{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

Technicolor corrections to b\bar{b} -> W^{\pm}\pi^{\mp}_t at the CERN Large Hadron Collider

In this paper we calculate the technicolor correction to the production of a charged top pion in association with a W boson via b\bar{b} annihilation at the CERN Large Hadron Collider in the context of the topcolor assisted technicolor model. We find that the cross section of pp \rightarrow b\bar{b} -> W^{\pm}\pi_t^{\mp} at the tree level can reach a few hundred femtobarns for reasonable ranges of the parameters, roughly corresponding to the result of the process pp -> b\bar{b} -> W^{\pm}H^{\mp} in the minimal supersymmetric standard model; the relative corrections arising from the one-loop diagrams are about a few percent to two dozen percent, and they will increase the cross section at the tree level. As a comparison, we also discuss the size of the hadron cross section via the other subprocess gg -> W^{\pm}\pi_t^{\mp}.Comment: 6 pages, 5 figure