Conjecture concerning the modes of excitation of the quark-gluon plasma

It is a widely held belief that at temperatures much higher than the confinement scale of quantumchromodynamics (QCD), quarks and gluons become free, giving rise to a new form of matter, called the quark-gluon plasma. It is conjectured here that the characterization of the plasma as a free or weakly interacting gas of quarks and gluons is valid only for short distances and short time scales of the order l/T, but that at scales larger than l/g2T (where g2 is the running QCD coupling) the plasma exhibits confining features similar to that of the low-temperature hadronic phase. The confining features are manifest in the long-range, i.e., long-wavelength, low-frequency, modes of the plasma. To examine the long-range real-time response of the plasma goes beyond the capabilities of current lattice-gauge-theory techniques. However, some properties of these modes can be determined indirectly. An attempt is made to characterize the long-range modes of excitation by examining the static high-temperature limit, focusing upon the static screening lengths of colored and neutral local operators. Since g2 is not small at temperatures likely to be accessible in heavy-ion collisions, the nonperturbative effects associated with vestiges of confinement are likely to be important in the phenomenological analysis of measurements made at accelerators.