EVOLUTION OF COUPLING-CONSTANT IN HOT QQCD

The evolution of QCD coupling constant at finite temperature is consid ered by making use of the finite temperature renormalization group equ ation up to the one-loop order in the background field method with the Feynman gauge and the imaginary time formalism. The results are compa red with the ones obtained in the literature. We point out, in particu lar, the origin of the discrepancies between different calculations, s uch as the choice of gauge, the breakdown of Lorentz invariance, imagi nary versus real time formalism and the applicability of the Ward iden tities at finite temperature.