Rare semileptonic decays of heavy mesons in the heavy quark limit

We study the branching ratios of D~+→D~0e~+v,D_s ~+→D~0e~+v, B_s~0→B~+e-v, D_s ~+→D~+e~-e~+ and B_s~0→B~0e~-e~+ rare semileptonic decay processes, which are induced by decays of light quarks, the heavy quarks remain unchanged. The branching ratios of these decay processes are estimated in the heavy quark limit and with SU(3) flavor symmetry. We find that the decay rates are very tiny in the framework of the Standard Model. We also estimate the sensitivities of the measurements of these rare decays at the future experiments, such as BES-Ⅲ, super-B and LHC-b. Observations of these decays may shed some light on new physics beyond the standard model.