Rare $Lambda_{b}to Lambdaell^{+}ell^{-}$ decay in the two-Higgs doublet model of type-III

The rare exclusive dileptonic $Lambda_{b}to Lambdaell^{+}ell^{-}$ $(ell =mu, tau)$ decays are investigated in the general two-Higgs-doublet model of type III. A significant enhancement to the branching ratios, differential branching ratios, leptons forward-backward asymmetry, and the $Lambda$ baryon polarizations over the standard model is obtained. Measurements of these quantities will be useful for establishing the two-Higgs doublet model.