Zero-density phase transition to quark-gluon plasma and the relativistic finite baryon volume effect in hadronic matter

We examine the role of relativistic finite baryon volume effect in the phas e transition between hadronic matter and quark-gluon plasma at vanishing ba ryon density. It is found that the appearance of abnormal state at high tem perature may enhance the baryon-antibaryon excitation, which has large infl uence on the quark-gluon plasma formation. The numerical results show that the occurrence of this phase transition depends on how to extrapolate the n ucleon-scalar meson coupling constant to the baryonic resonance-scalar meso n coupling.