Landau gauge ghost propagator and running coupling in SU(2) lattice gauge theory

Understand

We study finite (physical) volume and scaling violation effects of the Landau gauge ghost propagator as well as of the running coupling $\alpha_s(p)$ in the $SU(2)$ lattice gauge theory.

• We consider lattices with physical linear sizes between $aL \simeq 3$ fm and $7$ fm and values of lattice spacing between $a=0.2$ fm and $0.07$ fm.
• To fix the gauge we apply an efficient gauge fixing method aimed at finding extrema as close as possible to the global maximum of the gauge functional.
• We find finite volume effects to be small for the lattice size $aL \simeq 3$ fm at momenta $|p|\, \ge \, 0.6$ GeV.