Correlation of the ghost and the quark in the lattice Landau gauge QCD

Abstract

Effects of the quark field on the ghost propagator of the lattice Landau gauge are investigated by using the quenched gauge configuration of SU(2) first copy and the parallel tempering (PT) gauge fixed samples, quenched SU(3) $56^4$ configuration and unquenched SU(3) configurations produced by the MILC collaboration. We measure color symmetric and color antisymmetric ghost propagator and the Binder cumulant of $l^1$ norm and $l^2$ norm of color antisymmetric ghost propagator and investigate deviation from that of Gaussian distribution. The dynamical quarks make color antisymmetric ghost propagator closer to Gaussian distribution and Kugo-Ojima color confinement parameter $c$ closer to 1.