The Maximum Lifetime of the Quark–Gluon Plasma†

The width ∆T of the deconfinement transition region is shown to influence strongly the flow structure in the (Landau–) hydrodynamical expansion of a quark–gluon plasma. For a sharp first order transition (∆T = 0) the mixed phase is rather longlived, with a lifetime that has a maximum when the initial energy density is at the phase boundary between mixed and pure quark–gluon matter. For increasing ∆T , however, the lifetime decreases rapidly. Hadronic matter, however, remains long-lived as a consequence of the rapid change in the degrees of freedom in the transition region and the corresponding “softening” of the equation of state. † This work was supported by the Director, Office of Energy Research, Division of Nuclear Physics of the Office of High Energy and Nuclear Physics of the U.S. Department of Energy under Contract No. DE-FG-02-93ER-40764. Partially supported by the Alexander von Humboldt–Stiftung under the Feodor–Lynen program.