Study of A+A collisions in NA49 at the CERN SPS

The NA49 experiment performed an energy scan of particle production in Pb+Pb collisions through the CERN SPS range. Observed features in the energy dependence of pion and strangeness production can so far only be described by a model assuming deconfinement to set in at the early stage of the reaction at the lower SPS energies.     

Antiproton production in nucleon-nucleus and nucleus-nucleus collisions at the CERN-SPS

A model for antiproton production in nucleon-nucleus and nucleus-nucleus collisions at 200 GeV per nucleon, based on the Wounded Nucleon Model is developed. The predictions are compared to published nucleon-nucleus and sulphur-nucleus data. The results suggest the presence of similar antiproton production processes in nucleon-nucleus and nucleus-nucleus collisions near midrapidity.     

Search for the critical point of strongly interacting matter at the CERN SPS

The study of central collisions of heavy nuclei at CERN SPS energies by NA49 provided evidence for the onset of deconfinement around 30A GeV. Theoretical considerations predict a critical point of strongly interacting matter accessible in the SPS energy range. A search for the expected fluctuations has not yet found convincing signals. The strategy and plans for the continuation of this program at the SPS by NA61 with lighter nuclei is discussed.     

Further development of a model for the production of strange particles in nucleus-nucleus collisions

A previously proposed model for the production of neutral strange particles in nucleus-nucleus collisions, based on the Additive Quark Model and nuclear cascading, is further developed. The model predictions on neutral strange particle multiplicities, transverse momentum and rapidity distributions are compared with the existing oxygen- and sulphur-nucleus data at 200 GeV per nucleon. The predictions for central PbPb collisions are presented and discussed in some detail.     

Inclusive production of charged kaons in p+p collisions at 158 GeV/c beam momentum and a new evaluation of the energy dependence of kaon production up to collider energies

New data on the production of charged kaons in p+p interactions are presented. The data come from a sample of 4.8 million inelastic events obtained with the NA49 detector at the CERN SPS at 158 GeV/c beam momentum. The kaons are identified by energy loss in a large TPC tracking system. Inclusive invariant cross sections are obtained in intervals from 0 to 1.7 GeV/c in transverse momentum and from 0 to 0.5 in Feynman x. Using these data as a reference, a new evaluation of the energy dependence of kaon production, including neutral kaons, is conducted over a range from 3 GeV to $\mathrm{p}+\overline{\mathrm{p}}$ collider energies.     

Long-range correlations in hadron-nucleus interactions

An analysis of correlations in rapidity of charged particles produced in proton and antiproton interactions on hydrogen, argon and xenon at 200 GeV is presented. Positive long-range correlations are observed in interactions on heavy targets. The dependence of rapidity correlations between the forward and backward hemisphere on the number of projectile collisions is discussed.     

Production of neutral strange particles inpAr,pXe and\bar pXe collisions at 200 GeV

The production of neutral strange particles (K ⁰, ) inp Ar,pXe and Xe collisions at 200 GeV is investigated in the NA5 experiment using a streamer chamber at the CERN SPS. Results are presented on inclusive cross sections, average multiplicities, and on rapidity and transverse momentum distributions of neutral strange particles.     

Onset of deconfinement in nucleus-nucleus collisions

The energy dependence of hadron production in relativistic nucleus-nucleus collisions reveals anomalies-the kink, horn, and step. They were predicted as signals of the deconfinement phase transition and observed by the NA49 Collaboration in central PbPb collisions at the CERN SPS. This indicates the onset of the deconfinement in nucleus-nucleus collisions at about 30 A GeV.     

Results of the NA49 experiment on the search for the quark-gluon plasma at the CERN SPS

Experiment NA 49 at the CERN SPS has performed large acceptance measurements of hadron production in Pb+Pb collisions at 40 and 158 A-GeV beam energies. These data allowed a study of the space-time evolution, the hadro-chemical composition and event-by-event fluctuations of average event properties of the created hadron system. Results at top SPS energy are consistent with the existence of a transient deconfined phase in the early stage of the reaction.