Study of $B_{c}$$\to$$ J/\psi V $ and $B_{c}^{*}$$\to$$\eta_{c}V$ decays within the QCD factorization

Abstract

In this paper, we study the non-leptonic $B_{c}\to J/\psi V$ and $B_{c}^{*}\to\eta_{c}V$~$(V=\rho\,,K^{*})$ weak decays in the framework of QCD factorization. In the evaluation, the form factors are calculated by using the Bauer-Stech-Wirbel model and the light-front quark model, respectively. Besides the longitudinal amplitude, the power-suppressed transverse contributions are also evaluated at next-to-leading order. The predictions for the observables of $B_{c}\to J/\psi V$ and $B_{c}^{*}\to\eta_{c}V$ decays are presented. We find that the NLO QCD contribution presents about $ 8\%$ correction to the branching ratios, and the longitudinal polarization fractions of these decays are at the level of $(80\sim90)\%$. In addition, we suggest direct measurements on some useful ratios, $R_{K^{*}/\rho}^{(\lambda=0)}$ and $\widetilde{R}^{(\lambda=0)}_{K^{*}/\rho}$, which are very suitable for test the consistence between theoretical prediction and data because their theoretical uncertainties can be well-controlled.