Light-cone sum rules in soft-collinear effective theory

We derive light-cone sum rules (LCSRs) for exclusive B-meson decays into light energetic hadrons from correlation functions within soft-collinear effective theory (SCET). In these sum rules the short-distance scale refers to "hard-collinear" interactions with virtualities of order AQCD111b. Hard scales (related to virtualities of order m(b)(2)) are integrated out and enter via external coefficient functions ill the sum rule. Soft dynamics is encoded ill light-cone distribution amplitudes for the B-meson, which describe both the factorizable and non-factorizable contributions to exclusive B-meson decay amplitudes. As an example, we provide a detailed study of the SCET sum rule for the B -> pi transition form factor at large recoil, including radiative corrections from hard-collinear loop diagrams at first order in the strong coupling constant. We find remarkable conceptual and numerical differences with the heavy-quark limit of the conventional LCSR approach in QCD. (c) 2005 Elsevier B.V. All rights reserved.