INFRARED BEHAVIOR OF GLUON AND GHOST PROPAGATORS IN LANDAU GAUGE QCD

A truncation scheme for the Dyson-Schwinger equations of Euclidean QCD in Landau gauge is presented. It implements the Slavnov-Taylor identi ties for the three-gluon and ghost-gluon vertices, whereas irreducible four-gluon couplings as well as the gluon-ghost and ghost-ghost scatt ering kernels are neglected. The infrared behavior of gluon and ghost propagators is obtained analytically: The gluon propagator vanishes fo r small momenta, whereas the ghost propagator diverges strongly. The n umerical solutions are compared with recent lattice results. The runni ng coupling approaches a fixed point, alpha(c) similar or equal to 9.5 , in the infrared. [S0031-9007(97)04470-0].