Factorization of radiative leptonic decays of B−B− and D−D− mesons

In this work, we study the factorization of the radiative leptonic decays of B−B− and D−D− mesons, the contributions of the order O(ΛQCD/mQ)O(ΛQCD/mQ) are taken into account. The factorization is proved to be valid explicitly at the order O(αsΛQCD/mQ)O(αsΛQCD/mQ). The hard kernel is obtained. The numerical results are calculated using the wave-function obtained in relativistic potential model. The O(ΛQCD/mQ)O(ΛQCD/mQ) contribution is found to be very important, the correction to the decay amplitudes of B−→γeν¯ is about 20%–30%. For D   mesons, the O(ΛQCD/mQ)O(ΛQCD/mQ) contributions are more important.