Branching ratios of Bc→APB_c \to A P decays in the perturbative QCD approach

In this paper we calculate the branching ratios (BRs) of the 32 charmless hadronic $B_c \to A P$ decays ($A=a_1(1260),b_1(1235),K_1(1270),K_1(1400), f_1(1285),f_1(1420),h_1(1170),h_1(1380)$) by employing the perturbative QCD(pQCD) factorization approach. These considered decay channels can only occur via annihilation type diagrams in the standard model. From the numerical calculations and phenomenological analysis, we found the following results: (a) the pQCD predictions for the BRs of the considered $B_c$ decays are in the range of $10^{-6}$ to $10^{-8}$, while the CP-violating asymmetries are absent because only one type tree operator is involved here; (b) the BRs of $\Delta S= 0$ processes are generally much larger than those of $\Delta S =1$ ones due to the large CKM factor of $|V_{ud}/V_{us}|^2\sim 19$; (c) since the behavior for $^1P_1$ meson is much different from that of $^3P_1$ meson, the BRs of $B_c \to A(^1P_1) P$ decays are generally larger than that of $B_c \to A(^3P_1) P$ decays; (d) the pQCD predictions for the BRs of B_c \to (K_1(1270), K_1(1400)) \etap and $(K_1(1270), K_1(1400)) K$ decays are rather sensitive to the value of the mixing angle $\theta_K$.Comment: 1+17 pges, 1 figure, refs. added and some clarifications made, accepted for publication in Phys.Rev.

The production and decay of the top partner TT in the left-right twin higgs model at the ILC and CLIC

The left-right twin Higgs model (LRTHM) predicts the existence of the top partner $T$. In this work, we make a systematic investigation for the single and pair production of this top partner $T$ through the processes: e^{+}e^{-}\to t\ov{T} + T\bar{t} and T\ov{T}, the neutral scalar (the SM-like Higgs boson $h$ or neutral pseudoscalar boson $\phi^{0}$) associate productions e^{+}e^{-}\to t\ov{T}h +T\bar{t}h, T\ov{T}h, t\ov{T}\phi^{0}+T\bar{t}\phi^{0} and T\ov{T}\phi^{0}. From the numerical evaluations for the production cross sections and relevant phenomenological analysis we find that (a) the production rates of these processes, in the reasonable parameter space, can reach the level of several or tens of fb; (b) for some cases, the peak value of the resonance production cross section can be enhanced significantly and reaches to the level of pb; (c) the subsequent decay of $T\to \phi^{+}b \to t\bar{b}b$ may generate typical phenomenological features rather different from the signals from other new physics models beyond the standard model(SM); and (d) since the relevant SM background is generally not large, some signals of the top partner $T$ predicted by the LRTHM may be detectable in the future ILC and CLIC experiments.Comment: 20pages, 15 figures and 6 Tables. Minor corrections on text. new references adde