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 ΛQCDmbΛQCDmb. Hard scales (related to virtualities of order mb2) are integrated out and enter via external coefficient functions in the sum rule. Soft dynamics is encoded in 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→πB→π 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.