2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/177633The B-meson distribution amplitude is calculated using QCD sum rules. In particular we obtain an estimate for the integral relevant to exclusive B-decays λ_B = 460 \pm 110 MeV at the scale 1 GeV. A simple QCD-motivated parametrization of the distribution amplitude is suggested.17 pages, 8 figures, Latex styleHigh Energy Physics - Phenomenologytext