Re-examined radiative decay B*q → Bqγ in light-cone quantum chromodynamics

Abstract

The radiative decay B*q → Bqγ, (q = u, d or s) is re-examined using a modified light-cone quantum chromodynamics (QCD) sum rule method. In this method, adequate chiral operators are chosen as the interpolating fields in the correlators used for a sum rule estimate of the relevant coupling gB*qBqγ. Besides showing the physical picture consistent with the underlying physics in B*q → Bqγ, the resulting sum rule can effectively avoid the pollution by the nonlocal matrix element ⟨γ(q)|q̄(x)γμγ5q(0)|0⟩ starting with twist-3, about which little is known. Also, a comparison is made with the previous results from light-cone QCD sum rules and chiral perturbation theory.