Perturbative QCD Correction to the Light-Cone Sum Rule for the $B^{\ast }B\pi$ and $D^{\ast }D\pi$ Couplings

Abstract

The $B^{\ast }B\pi$ and $D^{\ast }D\pi$ couplings have previously been derived from a QCD light-cone sum rule in leading order. Here, we describe the calculation of the $O({\alpha }_s)$ correction to the twist 2 term of this sum rule. The result is used for a first next-to-leading order analysis. We obtain $g_{B^{\ast }B\pi }=22\pm 7$ and $g_{D^{\ast }D\pi }=10.5\pm 3$, where the error indicates the remaining theoretical uncertainty.

Comments: 11 pages, 1 figure, Latex, epsfig