Covariant light-front approach for $$B_c$$ decays into charmonium: implications on form factors and branching ratios

In this work, we investigate the form factors of $B_c$ decays into $J/\Psi, \psi(2S,3S)$, $\eta_c, \eta_c(2S,3S), \chi_{c0}, \chi_{c1}, h_c$ and $X(3872)$ mesons in covariant light-front quark model (CLFQM). For purpose branching ratio calculation, $B_c\to D^{(*)}, D^{(*)}_s$ transitions are also included. order to obtain for physical transition processes, need extend these from space-like region time-like region. The $q^2$-dependence each factor is plotted. Then, under factorization method, calculate ratios 80 decay channels with a charmonium involved mode. Most our predictions comparable results given by most other approaches. As radially excited state S-wave charmonia, such as $\psi(2S,3S)$ $\eta_c(2S,3S)$, involved, there two sets parameters their wave functions, corresponding scenario I (SI) II (SII), adopted ratios. Comparing future experimental data, one can discriminate which more favored.