NEW METHODS FOR THE RENORMALIZATION OF COMPOSITE OPERATOR GREEN-FUNCTIONS

New methods are developed for the renormalisation of composite operator Green functions, based on the idea of non-linear source renormalisation. The anomalous dimension in the renormalisation group equation (RGE) for the generating functional becomes a non-linear function of the sources, and extra terms are therefore induced in the RGEs for the Green functions. These methods are applied to the operator product expansion, and a simple RGE for the Wilson coefficients is presented. Applications are made to Green functions of conserved and anomalous currents.