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

TL;DR

This paper calculates the next-to-leading order perturbative QCD correction to the light-cone sum rule for $B^*B\pi$ and $D^*D\pi$ couplings, refining previous leading-order estimates with improved theoretical precision.

Contribution

It introduces the first $O(\alpha_s)$ correction to the sum rule for these couplings, providing more accurate theoretical predictions.

Findings

Calculated $O(\alpha_s)$ correction to the sum rule.

Provided updated estimates for $g_{B^*B\pi}$ and $g_{D^*D\pi}$.

Quantified the theoretical uncertainties in the couplings.

Abstract

The $B^*B\pi$ and $D^*D\pi$ 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 $g_{B^*B\pi}= 22\pm 7$ and $g_{D^*D\pi}=10.5\pm 3$, where the error indicates the remaining theoretical uncertainty.