The Infrared Behaviour of the Running Coupling in Landau Gauge QCD

Abstract

Approximate solutions for the gluon and ghost propagators as well as the running coupling in Landau gauge Yang-Mills theories are presented. These propagators obtained from the corresponding Dyson-Schwinger equations are in remarkable agreement with those of recent lattice calculations. The resulting running coupling possesses an infrared fixed point, ${\alpha }_S(0)=8.92/N_c$ for all gauge groups SU($N_c$). Above one GeV the running coupling rapidly approaches its perturbative form.

Comments: 8 pages, 3 figures, uses ActaStyle.cls, Invited talk given by R.A. at the conference RENORMALIZATION GROUP 2002, March 10 - 16, 2002, Strba, Slovakia