Non-ladder Extended Renormalization Group Analysis of the Dynamical   Chiral Symmetry Breaking
  The order parameters of dynamical chiral symmetry breaking in QCD, the dynamical mass of quarks and the chiral condensates, are evaluated by numerically solving the Non-Perturbative Renormalization Group (NPRG) equations. We employ an approximation scheme beyond ``the ladder'', that is, beyond the (improved) ladder Schwinger-Dyson equations. The chiral condensates are enhanced compared with the ladder ones, which is phenomenologically favorable. The gauge dependence of the order parameters is fairly reduced in this scheme. 
Ken-Ichi Aoki, Kaoru Takagi, Haruhiko Terao and Masashi Tomoyose