Hadronic Modes and Quark Properties in the Quark-Gluon Plasma

Based on interaction potentials between a heavy quark and antiquark as extracted from recent QCD lattice calculations, we set up a Brueckner-type many-body scheme to study the properties of light (anti-) quarks in a Quark-Gluon Plasma at moderate temperatures, $T\simeq$ 1-2 $T_c$. The quark-antiquark $T$-matrix, including both color-singlet and -octet channels, and corresponding quark self-energies and spectral functions are calculated self-consistently. The repulsive octet potential induces quasiparticle masses of up to 150 MeV, whereas the attractive color-singlet part generates resonance structures in the $q$-$\bar q$ $T$-matrix, which in turn lead to quasiparticle widths of $\sim$200 MeV. This corresponds to scattering rates of $\sim$1 fm$^{-1}$ and may reflect liquid-like properties of the system.