Light-cone sum rules for B→π form factors revisited

We reconsider and update the QCD light-cone sum rules for B ->pi form factors. The gluon radiative corrections to the twist-2 and twist-3 terms in the correlation functions are calculated. The (MS) over bar b-quark mass is employed, instead of the one-loop pole mass used in the previous analyses. The light-cone sum rule for f(B pi)(+)(q(2)) is fitted to the measured q(2)-distribution in B ->pi l nu(l), fixing the input parameters with the largest uncertainty: the Gegenbauer moments of the pion distribution amplitude. For the B ->pi vector form factor at zero momentum transfer we predict f(B pi)(+)(0)=0.26(-0.030)(+0.04). Combining it with the value of the product vertical bar V(ub)f(B pi)(+)(0)vertical bar extracted from experiment, we obtain vertical bar V-ub vertical bar=(3.5 +/- 0.4 +/- 0.2 +/- 0.1)x10(-3). In addition, the scalar and penguin B ->pi form factors f(B pi)(0)(q(2)) and f(B pi)(T)(q(2)) are calculated.