Study of Bc → DS decays in the perturbative QCD approach

Within the framework of the perturbative QCD approach based on k(T) factorization, we study 40 B-c -> DS decay modes in the leading order and leading power, where S stands for the light scalar meson. Under two different scenarios (S1 and S2) for the description of scalar mesons, we explore the branching fractions and related CP asymmetries. As a heavy meson consisting of two heavy quarks with different flavor, the light-cone distribution amplitude of the B-c meson has not been well defined, and therefore the delta function is adopted. We find that the contributions of emission diagrams are suppressed by the vector decay constants and Cabibbo-Kobayashi-Maskawa elements, and the contributions of annihilation are dominant. After the calculation, we also find that some branching fractions are in the range [10(-5); 10(-4)], which could be measured at the current LHCb experiment, and other decays with smaller branching fractions will be tested at high-energy colliders in the future. Furthermore, some decay modes have large CP asymmetries, but they are unmeasurable currently due to the small branching fractions.