Lattice data on QCD thermodynamics, especially recent study of high order susceptibilities by UK-Bielefeld Collaboration, have provided valuable information about matter properties around and above the critical temperature $T_c$. In this work we tried to understand what physical picture would explain these numerical data. We found two scenarios which will do it: (i) a quark quasiparticle gas, with the effective mass which is strongly decreasing near the phase boundary into the quark-gluon plasma (QGP) phase; or (ii) a picture including baryons at $T>T_c$, with the mass rapidly increasing across the phase boundary toward QGP. We further provide several arguments in favor of the latter scenario, one of which is a natural continuity with the baryon gas picture at $T<T_c$.

• Received 3 November 2005

DOI:https://doi.org/10.1103/PhysRevD.73.014509