B-π weak form factor with chiral current in the light-cone sum rules

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 $f_Bf^{+}_{B\pi}(q^2)$ 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.