The double charm decays of $B_c$ Meson in the Perturbative QCD Approach

Abstract

We make a systematic investigation on the double charm decays of $B_c$ meson, by employing the perturbative QCD approach based on $k_T$ factorization. It is found that the non-factorizable emission diagrams are not negligible in these channels. We predict the branching ratios of these $B_c$ decays and also the transverse polarization fractions of $B_c\to D_{(s)}^{\ast +}{\bar{D}}^{\ast 0},D_{(s)}^{\ast +}{D}^{\ast 0}$ decays, % where V denote the vector $D_{(s)}^{\ast }$ meson. We find that the magnitudes of the branching ratios of the decays $B_c\to D_s{\bar{D}}^0$ and $B_c\to D_s{D}^0$ are very close to each other, which are well suited to extract the Cabibbo-Kobayashi-Maskawa angle $\gamma$ through the amplitude relations. In addition, a large transverse polarization contribution that can reach $50$ is predicted in some of the $B_c$ meson decay to two vector charmed mesons.

Comments: 22 pages, 5 tables, to appear at PRD. arXiv admin note: text overlap with arXiv:1112.1257