The B¯ → π form factors from QCD and their impact on |V _ub |.

ABSTRACT: We revisit light-cone sum rules with pion distribution amplitudes to determine the full set of local B¯ → π 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

SUBMITTER: Leljak D 

PROVIDER: S-EPMC8266632 | biostudies-literature | 2021

REPOSITORIES: biostudies-literature