Does the QCD plasma contain propagating gluons?

Abstract

A comparison of two appropriately chosen screening masses of color singlet operators in the pure glue QCD plasma indicates that at sufficiently high temperature it contains a weakly interacting massive quasiparticle with the quantum numbers of the electric gluon. Still in the deconfined phase, but closer to T_c, the same mass ratio is similar to that at zero temperature, indicating that the propagating modes are more glueball-like, albeit with a lower scale for the masses. We observe a continuity between these two regimes.