ar X iv : h ep - p h / 97 10 32 3 v 1 1 3 O ct 1 99 7 Radiative Leptonic B Decays in the Light Front Model

Within the light front framework, we calculate the form factors for B → γ transitions directly in the entire physical range of momentum transfer. Using these form factors, we study the radiative decays of B → lνlγ and Bs(d) → νν̄γ. We show that the decay rates of B → lνlγ (l = e, μ) and B → νν̄γ are larger than that of the corresponding purely leptonic modes. Explicitly, in the standard model, we find that the branching ratios of B → μνμγ and Bs → νν̄γ are 3.7× 10 and 5.0× 10, in contrast with 3× 10 and 0 for B → μνμ and B → νν̄, respectively.