Study of the transverse mass spectra of strange particles in Pb-Pb collisions at 158 A GeV/c

The NA57 experiment has collected high statistics, high purity samples of \PKzS and \PgL, $\Xi$ and $\Omega$ hyperons produced in Pb-Pb collisions at 158 $A$ GeV/$c$. In this paper we present a study of the transverse mass spectra of these particles for a sample of events corresponding to the most central 53% of the inelastic Pb-Pb cross-section. We analyse the transverse mass distributions in the framework of the blast-wave model for the full sample and, for the first time at the SPS, as a function of the event centrality.Comment: 22 pages, 14 figures, submitted to J. Phys. G: Nucl. Phy

The silicon pixel detector (SPD) for the ALICE experiment

The ALICE silicon pixel detector (SPD) constitutes the two innermost layers of the inner tracking system (ITS). The basic building block of the SPD is the half-stave carrying two detector ladders. The half-stave is equipped with a multi-chip module (MCM) and an optical fibre link for control and readout. A 5-layer aluminium/polyimide bus ensures the distribution of power and signals on each half-stave. The half-staves are mounted on a light-weight carbon-fibre structure with an integrated evaporative cooling system. An overview of the SPD development and the current status of the construction are presented