Radiative Leptonic $B_c$ Decays

We analyze the radiative leptonic $B_c$ decay mode: $B_c \to \ell \nu \gamma$ ($\ell=e, \mu$) using a QCD-inspired constituent quark model. The prediction: ${\cal B}(B_c \to \ell \nu \gamma)\simeq 3 \times 10^{-5}$ makes this channel experimentally promising in view of the large number of $B_c$ mesons which are expected to be produced at the future hadron facilities.