The Quark Gluon Pion Plasma

Abstract

While it is commonly believed that there is a {\it direct} transition from the hadronic to a quark gluon phase at high temperature, it would be prejudicial to rule out a sequence of dynamically generated intermediate scales. Using as guide, an effective lagrangian with unconfined gluons and constituent quarks, interacting with a chiral multiplet, we examine a scenario in which the system undergoes first-order transitions at $T_{comp}$, the compositeness scale of the pions, at $T_{\chi}$, the scale for spontaneous chiral symmetry breaking, and at $T_c$, the confinement temperature. We find that at current energies, it is likely that the formation temperature of the plasma, $T_0 < T_{comp}$, and that this is therefore a quark gluon pion plasma (QGPP) rather than the usual quark gluon plasma (QGP). We propose some dilepton-related signatures of this scenario.Comment: Rewritten, new figure