Multipole-expanded soft-collinear effective theory with non-Abelian gauge symmetry

In position space the interaction terms of soft-collinear effective theory must be multipole-expanded to obtain interaction terms with homogeneous scaling behaviour. In this Letter we provide a manifestly gauge-invariant formulation of the theory after this expansion in the presence of non-Abelian gauge fields, extending our previous result. We give the effective Lagrangian (including the Yang-Mills Lagrangian for collinear and ultrasoft gluons) and heavy-to-light transition cur-rents to second order in the power expansion. paying particular attention to the field redefinitions that lead to the gauge symmetries of the effective Lagrangian. (C) 2002 Elsevier Science B.V. All rights reserved.