Bc meson rare decays in the light-cone quark model

We investigate the rare decays (B_{c} rightarrow D_{s}(1968)ell overline{ell}) and (B_{c}rightarrow D_{s}^{*}(2317) ell overline{ell}) in the framework of the light-cone quark model (LCQM). The transition form factors are calculated in the space-like region and then analytically continued to the time-like region via exponential parametrization. The branching ratios and longitudinal lepton polarization asymmetries (LPAs) for the two decays are given and compared with each other. The results are helpful for investigating the structure of B _c meson and for testing the unitarity of CKM quark mixing matrix. All these results can be tested in the future experiments at the LHC.