Radiative Leptonic Decays of $B_c$ Meson

Abstract

To the leading order, the radiative leptonic decays $B_c\to \gamma \ell \bar{\nu }$ ($\ell =e,\mu$) are studied carefully. In the study, a non-relativistic constituent quark model and the effective Lagrangian for the heavy flavour decays are used. As a result, the branching ratios turn out to be of the orders of $10^{-5}$ for $B_c\to \gamma \mu \bar{\nu }$ or for $B_c\to \gamma e\bar{\nu }$. Based on this study, we point out the decays being accessible experimentally at the future LHC, and the possibility to determine the decay constant $f_{B_c}$ through the radiative decays.

Comments: 9 pages Latex, including 2 figures