Infrared Properties of Hot Gauge Theories

por Oleg Kalashnikov (Lebedev Inst., Moscow)

jueves 25 feb. 1999 12:00 → 13:00 Europe/Madrid

Sala Seminarios (Dpto. de Fisica Teorica (UVEG))

The infrared limits of the gluon polarization tensor are analyzed in hot non-Abelian theories using perturbative and nonperturbative calculations. The calculations performed within the lowest one-loop order lead to the very important result: to the infrared fictitious pole of the gluon propagator which spoils the selfconsistency within any perturbative scheme. Within nonperturbative calculations there are two different possibilities to eliminate this difficulty: the nonanalytical logarithmic behaviour for small momenta and the finite limit of the order of g^2 T that is the so-called gluon magnetic mass. Both possibilities are analyzed. The next-to-leading order calculations are reviewed to present the nonperturbative screening potential within hot non-Abelian QCD and the Debye mass. The screening potential being calculating nonperturbatively does not correspond to the usual attractive QCD-Debye one and instead of that it is repulsive and power-behaved like 1/r^6 at large distance. The more exact calculations of the Debye mass are also reviewed briefly.