A. Andrighetto

Enhancement of strange and multi-strange hyperons and anti-hyperons in S-S and S-W interactions at 200 GeV/c

Strange and multistrange hyperon production is expected to be enhanced in heavy ion interactions if a phase transition from hadronic matter to a quark-gluon plasma takes place. The production yields of Λs, s, Ξ−s, and s relative to the production of negative particles are presented for p-W, p-S, S-W, and S-S interactions at 200 GeV/c per nucleon and compared to those from p-Pb and Pb-Pb interactions at 158 GeV/c per nucleon. In particular, enhancements of strange and multistrange hyperons will be presented where hyperon yields are normalized to the yields of negative particles.

Observation of Ω− and in sulphur-tungsten interactions at 200 GeV/c per nucleon

Abstract Multistrange baryon and antibaryon production is suggested to be a useful probe in the search for Quark-Gluon Plasma formation. We report the detection of an Ω − + Ω − signal in central S + W interactions at 200 A GeV/c and measure the ratio Ω − Ω − = 0.57±0.41 at central rapidity and p T >1.6 GeV/ c .

Ω/Ξ production ratio in S‐W

We have measured the (Ω−+Ω+)/(Ξ−+Ξ+) production ratio in central S‐W collisions to be 0.8±0.4 at central rapidity and pT≳1.6 GeV/c.

Λ and Ξ− production in proton‐tungsten interactions at 200 GeV/c per nucleon

The primary aim of the WA85 experiment is the study of strange and multistrange baryon and anti‐baryon production. Particles are detected in the kinematic window of central rapidity and pT≳1.0 GeV/c. Results on the production of Λ,u2009Λ,Ξ− and Ξ− hyperons in proton‐tungsten interactions from the 1990 run are presented and compared with the sulphur‐tungsten data.

Review of strange particle production from the WA85 Collaboration

Strange and, especially, multistrange baryon and anti‐baryon production is expected to be a useful probe in the search for Quark‐Gluon Plasma formation. A review of WA85 results on strange and multistrange particle production in SW and pW interactions at 200 GeV/c per nucleons is presented. In particular, mT distributions and relative ratios are presented for Ξ−s, Ξ−s, Λs, Λs, and K0s.

Charged kaon spectra in SW interactions at 200 GeV/c per nucleon

New results on the production of charged kaons in Sulphur‐Tungsten interactions have been obtained by the WA85 Collaboration. We present mt spectra for K+ and K− particles and the ratio <K+≳/<K−≳ calculated in the kinematic region pt≥0.9 GeV/c and 2.3≤ylab≤3.0.

Ω− signal in WA85

Abstract We have extracted from the full WA85 1990 data set a sample of 14ω − + ω − candidates. We describe the selection criteria, and give a measurement of the ω − /ω − ratio at central rapidity and PT > 1.6 GeV/ c .

OBSERVATION OF OMEGA- AND (OMEGA-)OVER-BAR IN SULFUR-TUNGSTEN INTERACTIONS AT 200 GEV/C PER NUCLEON

Abstract Multistrange baryon and antibaryon production is suggested to be a useful probe in the search for Quark-Gluon Plasma formation. We report the detection of an Ω − + Ω − signal in central S + W interactions at 200 A GeV/c and measure the ratio Ω − Ω − = 0.57±0.41 at central rapidity and p T >1.6 GeV/ c .