Form Factors from Light-Cone Sum Rules with B-Meson Distribution Amplitudes

Abstract

New sum rules for $B\to \pi ,K$ and $B\to \rho ,K^{\ast }$ form factors are derived from the correlation functions expanded near the light-cone in terms of B-meson distribution amplitudes. The contributions of quark-antiquark and quark-antiquark-gluon components in the B meson are taken into account. Models for the B-meson three-particle distribution amplitudes are suggested, based on QCD sum rules in HQET. Employing the new light-cone sum rules we calculate the form factors at small momentum transfers, including $SU(3{)}_{fl}$ violation effects. The results agree with the predictions of the conventional light-cone sum rules.

Comments: 32 pages, 7 figures, the discussion of numerical results extended, two references added, version to be published in Phys.Rev. D