Infrared exponents and running coupling of SU(N) Yang–Mills theories

We present approximate solutions for the gluon and ghost propagators as well as the running coupling in Landau gauge Yang–Mills theories. We solve the corresponding Dyson–Schwinger equations in flat Euclidean spacetime without any angular approximation. This supplements recently obtained results employing a four-torus, i.e., a compact spacetime manifold, as infrared regulator. We confirm previous findings deduced from an extrapolation with tori of different volumes: the gluon propagator is weakly vanishing in the infrared and the ghost propagator is highly singular. For non-vanishing momenta our propagators are in remarkable agreement with recent lattice calculations.