Nonabelian Debye screening in one-loop resummed perturbation theory

Abstract

Debye screening of static chromoelectric fields at high temperature is investigated at next-to-leading order through one-loop resummed perturbation theory. At this order the gluon propagator appears to give rise to strong deviations from a Yukawa form of screening. Generally, an oscillatory behavior is found which asymptotically becomes repulsive, but in a gauge-dependent manner. However, these features are strongly sensitive to the existence of screening of static magnetic fields. It is shown that a small magnetic screening mass can restore exponential screening with a gauge-independent value of the screening mass, which depends logarithmically on the magnitude of the magnetic mass. Recent results obtained in temporal axial gauge, which instead indicate an asymptotic (repulsive) power-law behaviour of screening, are also critically discussed. In order to arrive at a gauge-invariant treatment of chromoelectric screening, Polyakov loop correlations are considered, both with and without dynamical gauge symmetry breaking. Again a crucial sensitivity to the scale of magnetic screening is found. A detailed comparison of the perturbative results with recent high-precision lattice simulations of the SU(2) Polyakov loop correlator is made, which are found to agree well with the perturbative result in the symmetric phase when a magnetic mass ∼ g 2 T/4 is included.