Perturbative QCD correction to the light-cone sum rule for the B∗Bπ and D∗Dπ couplings

Abstract The B ∗ Bπ and D ∗ Dπ couplings have previously been derived from a QCD light-cone sum rule in leading order. Here, we describe the calculation of the O(αs) correction to the twist 2 term of this sum rule. The result is used for a first next-to-leading order analysis. We obtain g B ∗ Bπ =22±7 and g D ∗ Dπ =10.5±3 , where the error indicates the remaining theoretical uncertainty.