The (B)over-bar → π form factors from QCD and their impact on |Vub|

We revisit light-cone sum rules with pion distribution amplitudes to determine the full set of local (B) over bar -> pi form factors. To this end, we determine all duality threshold parameters from a Bayesian fit for the first time. Our results, obtained at small momentum transfer q(2), are extrapolated to large q(2) where they agree with precise lattice QCD results. We find that a modification to the commonly used BCL parametrization is crucial to interpolate the scalar form factor between the two q(2) regions. We provide numerical results for the form factor parameters - including their covariance - based on simultaneous fit of all three form factors to both the sum rule and lattice QCD results. Our predictions for the form factors agree well with measurements of the q(2) spectrum of the semileptonic decay (B) over bar (0) -> pi(+)l(-)(nu) over bar (l). From the world average of the latter we obtain vertical bar V-ub vertical bar = (3.77 +/- 0.15) . 10(-3), which is in agreement with the most recent inclusive determination at the 1 sigma level.