Semileptonic decay of Bc to ηc and J/ψ on the light front

We study the semileptonic decay of $B_c (0^-)$ to charmonia through bottom-to-charm-quark electroweak current in framework basis light-front quantization. Explicitly, we calculate weak transition form factors for processes $B_c$ decaying into $\eta_c$ or $J/\psi$ based on corresponding initial and final valence wave functions both obtained from also present differential width branching ratios, as well ratios decays $\eta_c'$ $\psi'$. observe unphysical frame dependence calculated factors, which is attributed only including functions. Based analysis component, propose a preferred set frames these factors.