부산대학교 도서관

NA57 has been specifically designed to study the onset of strange baryon and antibaryon enhancements in Pb-Pb with respect to p-Be collisions, first observed by the WA97 experiment at 160 A GeV/c beam momentum. The aim is to look for the dependence of these enhancements on the interaction volume, as measured by the number of wounded nucleons, and the energy per incoming nucleon. In NA57 the centrality range goes down to a lower limit of about 50 wounded nucleons, compared with about 100 in WA97. Data have been collected both at 160 and at 40 A GeV/c, while WA97 collected data only at the top SPS beam momentum of 160 A GeV/c. In this contribution we recall the main features of the NA57 experiment and we present the first results on ξ[sup -] and &ξmacr;[sup +] hyperon production in Pb-Pb collisions at 160 A GeV/c. [ABSTRACT FROM AUTHOR]