Study of strangeness enhancement in lead-lead collisions at the CERN SPS

A review of the latest results from the WA97 experiment on the strange particle production in Pb-Pb and p-Pb collisions is presented. Transverse mass spectra and yields of K/sub S//sup 0/, Lambda , Xi , Omega and h/sup -/ (negatively charged particles) have been measured at central rapidity. Yields are studied as a function of the number of nucleons participating in the collision N/sub part/. From p-Pb to Pb-Pb collisions the particle yields per participant increase substantially. The enhancement is more pronounced for multistrange particles and exceeds an order of magnitude for Omega. (28 refs)

Strange baryon production in p-Pb collisions at 158 GeV/c: a comparison with VENUS model

Lambda, Xi and Omega yields measured by the WA97 experiment at central rapidity in p-Pb interactions at 158 GeV/c are compared to those predicted by VENUS 4.12. The VENUS model, although in reasonable agreement with the Lambda and the negative particle data, fails to reproduce the data on multistrange baryons and anti-baryons

Λ,Ξ\Lambda, \Xi and Ω\Omega production at mid-rapidity in Pb-Pb and p-Pb collisions at 158 A GeV/c

Lambda, Xi and Omega yields and transverse mass spectra measured at central rapidity in Pb-Pb and p-Pb collisions at 158 A GeV/c are presented. The yields in Pb-Pb interactions are given as a function of the collision centrality and compared with those obtained from p-Pb collisions. The dependence of hyperon yields on the centrality of the impact and on the strangeness content of the hyperon are discussed

Strange and multistrange baryon production in Pb-Pb collisions at 158 A GeV/c

The series of experiments (WA85, WA94 and WA97) at the Omega spectrometer at CERN SPS have systematically studied the production of different strange particles. Strangeness enhancements at central rapidities have been reported by WA85 and WA94 in S-W and S-S with respect to p-A collisions. For the investigation of Pb-Pb interactions in the WA97 experiment a new detector suitable for high particle densities, the Pixel Tracking Chamber, has been developed based on silicon pixel detectors. The results on production ratios and cross sections of Lambda, , Xi(-), (+), Omega(-) and (+) detected by this experiment are presented. A significant enhancement of the Omega over Xi ratio is observed when comparing p-Pb to Pb-Pb data (a factor of about 3)