Non-perturbative Propagators, Running Coupling and Dynamical Mass Generation in Ghost-Antighost Symmetric Gauges in QCD

Abstract

We present approximate non-perturbative solutions for the propagators as well as the running coupling of QCD from a coupled system of renormalised, truncated Dyson--Schwinger equations. We employ ansaetze for the dressed vertices such that the running coupling and the quark mass function are independent of the renormalisation point. Our solutions are in good agreement with the results of recent lattice calculations. We find a weakly vanishing gluon propagator at small momenta and an infrared singular ghost propagator in agreement with Zwanziger's horizon condition and the Kugo-Ojima confinement criterion. The running coupling possesses an infrared fixed point at alpha(0) = 8.92/N_c. To investigate the influence of boundary conditions on the propagators we solved the ghost and gluon DSEs also on a four-torus. Our results show typical finite volume effects but are still close to the continuum solutions for sufficiently large volumes. For the quark propagator we find dynamically generated quark masses that agree well with phenomenological values. The effects of unquenching the system are found to be small. In particular the infrared behaviour of the ghost and gluon dressing functions found in pure Yang-Mills theory is almost unchanged as long as the number of light flavors is smaller than four.

163 pages, 36 figures, PhD-thesis, Univ. of Tuebingen. Nov 2002

References in corpus (6)

• Non-perturbative Propagators, Running Coupling and Dynamical Quark Mass of Landau gauge QCD
• On the infrared behaviour of Gluons and Ghosts in Ghost-Antighost symmetric gauges
• Running coupling constant and propagators in SU(2) Landau gauge
• Numerical Investigation of Fermion Mass Generation in QED
• Vortex induced confinement and the IR properties of Green functions
• Infrared Exponents and the Running Coupling of Landau gauge QCD and their Relation to Confinement

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• CrasyDSE: A framework for solving Dyson-Schwinger equations
• Solving a Set of Truncated Dyson-Schwinger Equations with a Globally Converging Method
• Solving the Ghost-Gluon System of Yang-Mills Theory on GPUs
• The Kugo-Ojima confinement criterion and the Infrared Behavior of Landau gauge QCD