Reexamined radiative Decay $ B_{q}^*\to B_{q}\gamma $ in Light Cone QCD

Abstract

The radiative decay $ B_{q}^*\to B_{q}\gamma(q=u,d, or s) $ is reexamined with a modified light-cone QCD sum rule method, in which adequate chiral operators are chosen as the interpolating fields in the correlators used for a sum rule estimate of the relevant coupling $ g_{B_{q}^*B_{q}\gamma} $. The resulting sum rules not only show the physical picture consistent with the underlying physics in $ B_{q}^*\to B_{q}\gamma $ but also avoid the pollution by the nonlocal matrix element $< \gamma(q) | \bar{q}(x) \gamma_{\mu}\gamma_{5}q(0) | 0>$, which starts with twist-3 and thus may bring a large uncertainty to the sum rule predictions. Also, a comparison is made with the previous results from light-cone QCD sum rules and chiral perturbation theory.