Production of strange and multistrange hadrons in nucleus-nucleus collisions at SPS

We report the main results from experiment WA97 on the production of strange and multistrange hadrons at midrapidity in Pb+Pb, p+Pb and p+Be collisions at 158~A~GeV/$c$. A comparison with some of the available models is presented

Transverse mass spectra of strange and multi-strange particles in Pb-Pb collisions at 158 A GeV/c

The WA97 experiment has measured the transverse mass (\mT) spectra fornegative hadrons (\hneg) and strange particles produced at mid--rapidity in Pb--Pb collisions. The increased statistics of analysed data samples allowed us to perform a study of the spectra of \PKzS, \PgL, $\mathrm{\Xi}$, $\mathrm{\Omega}$ and\hneg~as a function of the collision centrality. The data, whichcorrespond to the most central 40\% of the total inelastic cross section,have been divided into four centrality classes according to the estimated numberof nucleons taking part in the collision. The \mT~ spectra, analysed separatelyfor each centrality bin, exhibit only weak ($\leq$ 15\%) centrality dependence. The deviation of the$\mathrm{\Omega}$ inverse slope from the linear dependence on the particle massis confirmed even for the most central Pb--Pb collisions

LHC1: a semiconductor pixel detector readout chip with internal, tunable delay providing a binary pattern of selected events

The Omega3/LHCl pixel detector readout chip comprises a matrix of 128 X 16 readout cells of 50 mu m X 500 mu m and peripheral functions with 4 distinct modes of initialization and operation, together more than 800 000 transistors. Each cell contains a complete chain of amplifier, discriminator with adjustable threshold and fast-OR output, a globally adjustable delay with local fine-tuning, coincidence logic and memory. Every cell can be individually addressed for electrical test and masking, First results have been obtained from electrical tests of a chip without detector as well as from source measurements, The electronic noise without detector is similar to 100 e(-) rms. The lowest threshold setting is close to 2000 e(-) and non-uniformity has been measured to be better than 450 e(-) rms at 5000 e(-) threshold. A timewalk of < 10 ns and a precision of < 6 ns rms on a delay of 2 mu s have been measured. The results may be improved by further optimization

Hyperon production in proton-sulphur collisions at 200 GeV/c

The WA94 experiment uses the production of strange particles and antiparticles to investigate the properties of hot hadronic matter created in heavy--ion interactions. \PgL, \PagL, \PgXm\ and \PagXp\ particle yields and transverse mass spectra are presented for pS interactions. These results are compared with those from SS interactions. Our results are also compared with those from pW and SW interactions of the WA85 experiment