B-meson distribution amplitude from the B→π form factor

Employing the light-cone sum rule approach in QCD, we relate the B-meson distribution amplitude to the B→π form factor at zero momentum transfer. In leading order, the sum rule is converted into a simple expression for the inverse moment λB of the distribution amplitude ϕ+B. Using as an input the B→π form factor calculated from the light-cone sum rule in terms of pion distribution amplitudes, we obtain an estimate: λB=460±160MeV. We investigate how this result is modified by the B-meson three-particle distribution amplitudes.