Eur. Phys. J. C (2007) 51: 633-644
https://doi.org/10.1140/epjc/s10052-007-0302-y

Regular Article - Theoretical Physics

Following gluonic world lines to find the QCD coupling in the infrared

Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 19, 69120, Heidelberg, Germany

^* e-mail: dima@tphys.uni-heidelberg.de

Received: 23 February 2007
Published online: 31 May 2007

Abstract

Using a parametrization of the Wilson loop with the minimal-area law, we calculate the polarization operator of a valence gluon, which propagates in the confining background. This enables us to obtain the infrared freezing (i.e. finiteness) of the running strong coupling in the confinement phase, as well as in the deconfinement phase up to the temperature of dimensional reduction. The momentum scale defining the onset of freezing is found both analytically and numerically. The nonperturbative contribution to the thrust variable, originating from the freezing, makes the value of this variable closer to the experimental one.