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

摘要

The WA97 experiment has measured the transverse mass (m_T) spectra for negative hadrons (h~-) 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 K_S~0, Λ, Ξ, Ω and h~- as a function of the collision centrality. The data, which correspond to the most central 40% of the total inelastic cross section, have been divided into four centrality classes according to the estimated number of nucleons taking part in the collision. The m_T spectra, analysed separately for each centrality bin, exhibit only weak (≤15%) centrality dependence. The deviation of the Ω inverse slope from the linear dependence on the particle mass is confirmed even for the most central Pb-Pb collisions.