Probing the equation of state in Au+Au at 11 GeV/nucleon with(3+1)-dimensional hydrodynamics

Abstract

The effect of (i) the phase transition between a quark gluon plasma (QGP) and a hadron gas and (ii) the number of resonance degrees of freedom in the hadronic phase on the single inclusive distributions of 16 different types of produced hadrons for Au+Au collisions at the Brookhaven Alternating Gradient Synchroton (AGS) energies is studied. We have used an exact numerical solution of the relativistic hydrodynamical equations {ital without free parameters} which, because of its (3+1)-dimensional character, constitutes a considerable improvement over the classical Landau solution. We assume chemical equilibration and we use two different equations of state (EOS): one describing a phase transition from QGP to the hadronic phase and two versions of a purely hadronic EOS; we find that the first one gives an overall better description of the Au+Au experimental data at AGS energies. We reproduce and analyze measured meson and proton spectra and also make predictions for antiprotons, deltas, antideltas, and hyperons. The low m{sub t} enhancement in {pi}{sup {minus}} spectra is explained by baryon number conservation and strangeness equilibration. The sensitivity of various production channels to the EOS is analyzed. {copyright} {ital 1997} {ital The American Physical Society}