1203.1359 (Aoife Bharucha)

Two-loop Corrections to the B to pi Form Factor from QCD Sum Rules on
the Light-Cone and |V(ub)|    [PDF]

Aoife Bharucha

We calculate the leading-twist O(alphas^2 beta0) corrections to the B to pi transition form factor f+(0) in light-cone sum rules. We find that, as expected, there is a cancellation between the O(alphas^2 beta0) corrections to fB f+(0) and the large corresponding corrections to fB, calculated in QCD sum rules. This suggests the insensitivity of the form factors calculated in the light-cone sum rules approach to this source of radiative corrections. We further obtain an improved determination of the CKM matrix element |V(ub)|, using latest results from BaBar and Belle for f+(0)|V(ub)|.

View original: http://arxiv.org/abs/1203.1359