Properties of the Faddeev-Popov operator in the Landau gauge, matter   confinement and soft BRST breaking
  In light of the development of the Gribov issue for pure Euclidean gauge theories and of the recent lattice measurement of soft breaking of the BRST invariance in Yang-Mills theories in the Landau gauge, we consider non-perturbative features in the gauge-interacting matter sector and their relation with general properties of the Faddeev-Popov operator. A signature for BRST breaking in the matter sector is proposed and a local and renormalizable framework is constructed, accommodating this signature and predicting non-perturbative matter propagators that are consistent with available lattice data for adjoint scalars and quarks. 
M. A. L. Capri, M. S. Guimaraes, I.F. Justo, L. F. Palhares, S. P.   Sorella
hep-th hep-ph nucl-th