Signatures of Quark-Gluon-Plasma formation in high energy heavy-ion collisions: A critical review

A critical review on signatures of Quark-Gluon-Plasma formation is given and the current (1998) experimental status is discussed. After giving an introduction to the properties of QCD matter in both, equilibrium- and non-equilibrium theories, we focus on observables which may yield experimental evidence for QGP formation. For each individual observable the discussion is divided into three sections: first the connection between the respective observable and QGP formation in terms of the underlying theoretical concepts is given, then the relevant experimental results are reviewed and finally the current status concerning the interpretation of both, theory and experiment, is discussed. A comprehensive summary including an outlook towards RHIC is given in the final section.Comment: Topical review, submitted to Journal of Physics G: 68 pages, including 39 figures (revised version: only minor modifications, some references added

Hadron production in nuclear collisions from the NA49 experiment at 158GeV/c · A

With its large acceptance and particle identification coverage the NA49 experiment (Fig. 1) can study hadron production in a wide range of high energy reactions [1]. Originally aimed at examining central Pb+Pb collisions for signatures of quark-gluon plasma formation, the scope of the experiment has been enhanced with a systematic study of impact parameter and projectile size dependence, as well as the inclusion of the more elementary p+p and p+A interactions. The question is: are predicted signals of the quark-gluon plasma observed and are there discontinuities which would support the concept of hadronic phase transition

Production of multi-strange hyperons and strange resonances in the NA49 experiment

The NA49 large-acceptance hadron spectrometer has measured strange and multi-strange hadrons from Pb + Pb and p + p collisions at the CERN SPS. Preliminary results for the transverse mass and rapidity distributions for - and + from central Pb + Pb collisions at 158 GeV c-1/nucleon are presented. Fully integrated yields per event of 4.42± 0.31 and 0.74± 0.04 are found for - and +, respectively, leading to a 4π +/- ratio of 0.17± 0.02. The ratio +/- at mid-rapidity is found to be 0.22 ± 0.04, agreeing with previously published values. In addition, preliminary data on the ∧(1520) and φ(1020) resonances are presented. The ∧(1520) multiplicity for p + p collisions is found to be 0.012 ± 0.003. No signal is observed for Pb + Pb collisions and a production upper limit of 1.36 ∧(1520) per event indicates an apparent suppression when comparing with scaled p + p data. Integrated φ(1020) yields per event are found to be 7.6 ± 1.1 for Pb + Pb and 0.012 ± 0.0015 for p + p collisions. No significant shift or broadening of the φ(1020) invariant mass distribution is observed in central Pb + Pb collisions. © 2001 IOP Publishing Ltd

Centrality dependence of directed and elliptic flow at the SPS

New data with a minimum bias trigger for 158 GeV/nucleon Pb + Pb have been analyzed. Directed and elliptic flow as a function of rapidity of the particles and centrality of the collision are presented. The centrality dependence of the ratio of elliptic flow to the initial space elliptic anisotropy is compared to models