Rare radiative decays of the $B_c$ meson

In this paper, we study the rare radiative processes within the Standard Model, where stands for the meson , or . During the investigations, we consider the contributions from the penguin, annihilation, color-suppressed and color-favored cascade diagrams. Our results show that: (1) the penguin and annihilation contributions are dominant in the branching fractions; (2) for the processes and , the effects from the color-suppressed and color-favored cascade diagrams are un-negligible.