Speaker
Description
The $B_c$ meson provides a useful laboratory for investigating heavy-quark dynamics and weak decays involving two heavy flavors. In this work, we study the dependence of the $B_c\to\eta_c$ and $B_c\to J/\psi$ transition form factors and corresponding decay observables on the $B_c$-meson mass. The $B_c$ mass is obtained within a semi-relativistic potential-model framework using Hydrogenic and Gaussian radial-wave-function prescriptions, leading to different mass inputs. Numerical transition form factors obtained from QCD sum-rule calculations are parametrized over the relevant kinematic region using the Bourrely-Caprini-Lellouch ($z$-) expansion. These parametrizations are subsequently used to calculate semileptonic and nonleptonic decay widths and branching ratios for the $B_c\to\eta_c$ and $B_c\to J/\psi$ channels. We compare the resulting form factors and decay observables for the different $B_c$ mass inputs and quantify the associated numerical variations. The form factors at maximum recoil exhibit relatively small variations, whereas the integrated decay observables show more noticeable sensitivity in several channels. The results highlight the dependence of heavy-flavor decay phenomenology on the bound-state description and the corresponding mass input, providing a study of theoretical-systematic effects in $B_c$ meson decays.