On the leading OPE corrections to the ghost-gluon vertex and the Taylor   theorem
  This brief note is devoted to a study of genuine non-perturbative corrections to the Landau gauge ghost-gluon vertex in terms of the non-vanishing dimension-two gluon condensate. We pay special attention to the kinematical limit which the bare vertex takes for its tree-level expression at any perturbative order, according to the well-known Taylor theorem. Based on our OPE analysis, we also present a simple model for the vertex, in acceptable agreement with lattice data. 
Ph. Boucaud, D. Dudal, J. P. Leroy, O. P\'ene, J. Rodr\'iguez-Quintero
hep-ph