| Popis: |
Abstract We consider the form factors for the radiative semileptonic decays B ¯ $$ \overline{B} $$ (v) → D (*)(v′)ℓ ν ¯ $$ \overline{\nu} $$ ℓ γ in the kinematic region where the photon momentum, k, is small enough that heavy quark symmetry (HQS) can be applied without the radiated photon changing the heavy quark velocity (i.e., v (′) ∙ k < m (b,c)). We find that HQS is remarkably powerful, leaving only four new undetermined form factors at leading order in 1/m (b,c). In addition, one of them is fixed in terms of the leading order Isgur-Wise function in the kinematic region, v (′) ∙ k < ΛQCD. |
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