Systematic analysis of the form factors of $B_c\rightarrowη_c$, $J/ψ$ and corresponding weak decays

Abstract

The form factors of $B_c\rightarrowη_c$ and $B_c\rightarrow J/ψ$ are analyzed in the framework of three-point QCD sum rules. In these analyses, the contributions of the vacuum condensate terms $\langle g_{s}^{2}GG\rangle$ and $\langle g_{s}^{3}GGGf\rangle$ are considered. In addition, the decay widths and branching ratios of several decay channels are obtained by using the calculated form factors. These decay processes include the nonleptonic decays of $B_c^- \to η_c π^-$, $η_c K^-$, $η_c ρ^-$, $η_c K^{*-}$, $B_c^- \to J/ψπ^-$, $J/ψK^-$, $J/ψρ^-$, $J/ψK^{*-}$, and the semileptonic decays of $B_c^- \to η_c \mathcal{l} \barν$, $B_c^- \to J/ψ\mathcal{l} \barν$. These results about the form factors and decay properties of $B_c$ meson provide useful information for us to study the heavy-quark dynamics and find new physics(NP) beyond Standard Model(SM).