Nonperturbative structure of the quark-gluon vertex

Abstract

The complete tensor structure of the quark-gluon vertex in Landau gauge is determined at two kinematical points (`asymmetric' and `symmetric') from lattice QCD in the quenched approximation. The simulations are carried out at β = 6.0, using a mean-field improved Sheikholeslami-Wohlert fermion action, with two quark masses ~ 60 and 115 MeV. We find substantial deviations from the abelian form at the asymmetric point. The mass dependence is found to be negligible. At the symmetric point, the form factor related to the chromomagnetic moment is determined and found to contribute significantly to the infrared interaction strength.