Bochum 1998 – wissenschaftliches Programm
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HK: Hadronen und Kerne
HK 55: Structure of Baryons, Mesons VIII, Theory
HK 55.6: Gruppenbericht
Mittwoch, 18. März 1998, 15:45–16:15, J
The Infrared Behaviour of Gluon and Ghost Propagators in Landau Gauge QCD — •R. Alkofer1, L. von Smekal2, and A. Hauck1 — 1Institut f"ur Theoretische Physik, Universit"at T"ubingen, 72076 T"ubingen — 2Universit"at Erlangen–N"urnberg, Institut f"ur Theoretische Physik III, Staudtstr. 7, 91058 Erlangen
A truncation scheme for the Dyson–Schwinger equations of QCD in Landau gauge is presented which implements the Slavnov–Taylor identities for the 3–point vertex functions. For the pure gauge theory without quarks the resulting system of equations for the propagators of gluons and ghosts is solved in an approximation which allows for an analytic discussion of its solutions in the infrared: The gluon propagator is shown to vanish for small spacelike momenta whereas the ghost propagator is found to be infrared enhanced [1]. The running coupling of the non–perturbative subtraction scheme approaches an infrared stable fixed point at a critical value of the coupling, αc ≃ 9.5. The gluon propagator is shown to have no Lehmann representation. The results for the propagators obtained here compare favorably with recent lattice calculations.
[1] L. v. Smekal, A. Hauck and R. Alkofer, Phys. Rev. Lett. 79 (1997) 3591; hep-ph/9707327, submitted to Ann. Phys.
Supported in part by the Deutsche
Forschungsgemeinschaft (DFG) under contract
Al 279/3-1.