Hydrodynamical analysis of symmetric nucleus-nucleus collisions at CERN/SPS energies

We present a coherent theoretical study of ultrarelativistic heavy-ion data obtained at the CERN/SPS by the NA35/NA49 Collaborations using 3+1-dimensional relativistic hydrodynamics. We find excellent agreement with the rapidity spectra of negative hadrons and protons and with the correlation measurements in two experiments: $S+S$ at 200 $AGeV$ and $Pb+Pb$ at 160 $AGeV$ (preliminary results). Within our model this implies that for $Pb+Pb$ ($S+S$) a quark-gluon-plasma of initial volume 174 $fm^3$ (24 $fm^3$) with a lifetime 3.4 $fm/c$ (1.5 $fm/c$) was formed. It is found that the Bose-Einstein correlation measurements do not determine the maximal effective radii of the hadron sources because of the large contributions from resonance decay at small momenta. Also within this study we present an NA49 acceptance corrected two-pion Bose-Einstein correlation function in the invariant variable, $Q_{inv}$.