Conference paper
The Kugo-Ojima confinement criterion and the infrared behaviour of Landau gauge QCD
Reinhard Alkofer
; Universität Tübingen, Institut für Theoretische Physik, Auf der Morgenstelle 14, D-72076 Tübingen, Germany
Christian S. Fischer
; Universität Tübingen, Institut für Theoretische Physik, Auf der Morgenstelle 14, D-72076 Tübingen, Germany; Universität Heidelberg, Institut für Theoretische Physik, Philosophenweg 16, D-69120 Heidelberg, Germany
Abstract
Recent investigations of the Dyson-Schwinger equations and Monte-Carlo lattice calculations resulted in a coherent description of the fully dressed gluon, ghost and quark propagators in Landau gauge QCD. In the Dyson-Schwinger approach, the infrared behaviour of these propagators is determined analytically. For finite spacelike momenta the gluon, ghost and quark propagators are compared to available corresponding results of lattice Monte-Carlo calculations. For all three propagators, an almost quantitative agreement is found. These results for the non-perturbative propagators allow an analytical verification of the Kugo-Ojima confinement criterion. Our numerical analysis clearly reveals positivity violation for the gluon propagator generated by a cut in the complex momentum plane. The non-perturbative strong running coupling resulting from these propagators possesses an infrared fixed point. The quark propagator obtained from quenched and unquenched calculations displays dynamical chiral symmetry breaking with quark masses close to "phenomenological" and lattice values. We confirm that linear extrapolations of the quark propagator for different bare masses to the chiral limit are inaccurate.
Keywords
confinement; Dyson-Schwinger equations; dynamical chiral symmetry breaking
Hrčak ID:
305608
URI
Publication date:
1.3.2004.
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