New gauge boson $$W^\prime $$ W ′ and radiative leptonic decays of charged B and D mesons

Abstract Considering the constraints on model parameters from the latest experimental data, we study the contributions of new gauge boson $$W^\prime $$ W′ predicted by the general 221 models to the radiative leptonic decays of charged B and D mesons. It is found that the largest contributions of $$W^\prime $$ W′ in the non-universal 221 model to the branching fractions occur in the decay modes $$B^{-} \rightarrow \gamma \mu ^{-} \bar{\nu }_\mu $$ B-→γμ-ν¯μ and $$B^{-} \rightarrow \gamma \tau ^{-} \bar{\nu }_\tau $$ B-→γτ-ν¯τ , which can reach to about $$8 \%$$ 8% of the corresponding SM values in the up-quark mixing scenario. In contrast, the relative corrections of $$W^\prime $$ W′ predicted by the un-unified 221 model to the branching fractions are very tiny and identical for all the decay modes.