Generalized Heavy-to-Light Form Factors in Light-Cone Sum Rules

Abstract

We study the form factors for a heavy meson into the S-wave $K\pi /\pi \pi$ system with an invariant mass below 1~GeV. The mesonic final state interactions are described in terms of the scalar form factors, which are obtained from unitarized chiral perturbation theory. Employing generalized light-cone distribution amplitudes, we compute the heavy-to-light transition using light-cone sum rules. Our approach simultaneously respects constraints from analyticity and unitarity, and also takes advantage of the power expansion in the $1/m_b$ and the strong coupling constant.

Comments: 8 pages, 3 figures, v2: 11 pages, 3 figures, title changed, some clarifications and references added, matches version to appear in Physics Letters B