The infrared behavior of the quark propagator is studied at one loop and in the Landau gauge () using the screened massive expansion of full QCD and three different resummation schemes for the quark self-energy. The shift of the expansion point of perturbation theory, which defines the screened expansion, together with a nonstandard renormalization of the bare parameters, proves sufficient to describe the dynamical generation of an infrared quark mass also in the chiral limit. Analytically, the scale for such a mass is set by a mass parameter , whose value is fixed by a fit to the lattice data for quenched QCD. The quark mass function is shown to be in very good agreement with the lattice results. The quark function, on the other hand, shows the wrong qualitative behavior in all but one of the studied resummation schemes, where its behavior is qualitatively correct, but only at sufficiently high energies.

Screened massive expansion of the quark propagator in the Landau gauge

Comitini G.
;
Siringo F.
2021-01-01

Abstract

The infrared behavior of the quark propagator is studied at one loop and in the Landau gauge () using the screened massive expansion of full QCD and three different resummation schemes for the quark self-energy. The shift of the expansion point of perturbation theory, which defines the screened expansion, together with a nonstandard renormalization of the bare parameters, proves sufficient to describe the dynamical generation of an infrared quark mass also in the chiral limit. Analytically, the scale for such a mass is set by a mass parameter , whose value is fixed by a fit to the lattice data for quenched QCD. The quark mass function is shown to be in very good agreement with the lattice results. The quark function, on the other hand, shows the wrong qualitative behavior in all but one of the studied resummation schemes, where its behavior is qualitatively correct, but only at sufficiently high energies.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11769/513965
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