Spectral Properties of Quarks in the Quark-Gluon Plasma

We analyze the spectral properties of the quark propagator above the critical temperature for the deconfinement phase transition in quenched lattice QCD using clover improved Wilson fermions. The bare quark mass dependence of the quark spectral function is analyzed by varying the hopping parameter \kappa in Landau gauge. We assume a two-pole structure for the quark spectral function, which is numerically found to work quite well for any value of \kappa. It is shown that in the chiral limit the quark spectral function has two collective modes that correspond to the normal and plasmino excitations, while it is dominated by a single-pole structure when the bare quark mass becomes large.