Münster 2002 – scientific programme
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HK: Physik der Hadronen und Kerne
HK 8: Plenary Session
HK 8.1: Plenary Talk
Tuesday, March 12, 2002, 08:30–09:00, Plenarsaal
Aspects of Confinement in QCD: The Glue of Strong Interactions — •Lorenz von Smekal — Universität Erlangen-Nürnberg
In QED, the charge of a particle is of long-range nature. It can exist because the photon is massless. Localized objects are neutral like atoms. Without symmetry breaking, or Higgs mechanism, particles carrying the charges of the gauge group must be non-local objects. With mass gap such objects cannot exist in QCD, and all hadrons are thus color-neutral. Here, I present two approaches to study this phenomenon.
Charged states are always possible with suitable boundary conditions in a finite volume. This allows to study their fate in the thermodynamic limit from Monte-Carlo simulations on finite lattices. Suggesting the picture of a dual Meissner effect, the confinement of electric and the condensation of magnetic charges can be demonstrated in this way.1
In the covariant continuum formulation, the conditions for confinement relate to the infrared behavior of gluon and ghost correlations. Confinement is then encoded in critical infrared exponents.2
The necessity of fixing a gauge in this formulation is affected by the
Gribov problem. This problem, ways to by-pass it, and
implications on the mass gap and confinement are discussed.
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1 Ph. de Forcrand and L. von Smekal, preprint [hep-lat/0107018].
2 R. Alkofer and L. von Smekal, Physics Reports 353/5-6 (2001) 281.