Static correlation lengths in QCD at high temperatures and finite densities

We use a perturbatively derived effective field theory and three-dimensiona l lattice simulations to determine the longest static correlation lengths i n the deconfined QCD plasma phase at high temperatures (T greater than or s imilar to 2T(c)) and finite densities (mu less than or similar to 4T). For vanishing chemical potential, we refine a previous determination of the Deb ye screening length, and determine the dependence of different correlation lengths on the number of massless flavours as well as on the number of colo urs. For non-vanishing but small chemical potential, the existence of Debye screening allows us to carry out simulations corresponding to the full QCD with two (or three) massless dynamical flavours, in spite of a complex act ion. We investigate how the correlation lengths in the different quantum nu mber channels change as the chemical potential is switched on. (C) 2000 Els evier Science B.V. All rights reserved.