$B-\pi$ weak form factor with chiral current in the light-cone sum rules

Abstract

In this article, we calculate the $B\to \pi$ transition form factor $f_{B\pi }^{+}(q^2)$ by including perturbative $O({\alpha }_s)$ corrections to the twist-2 terms with chiral current in the light-cone QCD sum rule approach. The corrections to the product $f_B{f}_{B\pi }^{+}(q^2)$ in the leading twist approximation is found to be about 30%, while a similar magnitude corresponding to $O({\alpha }_s)$ corrections for $f_B(q^2)$ in the two-point sum rule cancel them and result in small net corrections for $f_{B\pi }^{+}(q^2)$. Our results confirm the observations made in previous light-cone QCD sum rule studies.

Comments: 8 pages, 6 figures, to appear in Phys.Rev.D