Running coupling in the conformal window of large-Nf QCD

Understand

Quantum Chromodynamics with a relatively large number of fundamentally charged quark flavours in the chiral limit is considered.

• A self-consistent solution of the quark, gluon and ghost propagator Dyson-Schwinger equations in Landau gauge exhibits a phase transition.
• Above the critical number of fermion flavours the non-perturbative running coupling develops a plateau over a wide momentum range, and the propagators follow a power law behaviour for these momenta.
• Hereby, the critical number of quark flavours depends crucially on the beyond-tree-level tensor structures of the quark-gluon vertex.