Decay $B_c^{+}\to D_{(s)}^{(\ast )+}{\mathrm{\ell }}^{+}{\mathrm{\ell }}^{-}$ within covariant confined quark model

We study the rare semileptonic decays of $B_c$ mesons within the effective field theoretical framework of covariant confined quark model. The transition form factors corresponding to $B_c^{+}\to D^{(\ast )+}$ and $B_c^{+}\to D_s^{(\ast )+}$ are computed in the entire $q^2$ range. Using form factors, we compute the branching fractions and compare them with the available theoretical results. We also compute various physical observables such as forward-backward asymmetry, longitudinal and transverse polarizations as well as clean angular observables.