Quark-gluon vertex from the Landau gauge Curci-Ferrari model

Abstract

We investigate the quark-gluon three-point correlation function within a one-loop computation performed in the Curci-Ferrari massive extension of the Faddeev-Popov gauge-fixed action. The mass term is used as a minimal way for taking into account the influence of the Gribov ambiguity. Our results, with renormalization-group improvement, are compared with lattice data. We show that the comparison is in general very satisfactory for the functions which are compatible with chiral symmetry, except for one. We argue that this may be due to large systematic errors {when extracting this function from} lattice simulations. The quantities which break chiral symmetry are more sensitive to the details of the renormalization scheme. We however manage to reproduce some of them with good precision. The chosen parameters allow to simultaneously fit the quark mass function coming from the quark propagator with a reasonably agreement.