F. Riggi

The ALICE Silicon Pixel Detector: readiness for the first proton beam

The Silicon Pixel Detector (SPD) is the innermost element of the ALICE Inner Tracking System (ITS). The SPD consists of two barrel layers of hybrid silicon pixels surrounding the beam pipe with a total of ≈ 107 pixel cells. The SPD features a very low material budget, a 99.9% efficient bidimensional digital response, a 12 μm spatial precision in the bending plane (r) and a prompt signal as input to the L0 trigger. The SPD commissioning in the ALICE experimental area is well advanced and it includes calibration runs with internal pulse and cosmic ray runs. In this contribution the commissioning of the SPD is reviewed and the first results from runs with cosmic rays and circulating proton beams are presented.

Results on hyperon production from CERN NA57 experiment

Recent results on hyperon production in Pb-Pb collisions from the NA57 experiment are reported. Strangeness enhancements and the transverse mass spectra properties at 158 GeV per nucleon are described.

Centrality dependence of strange baryon yields in Pb-Pb collisions

New data on strange baryon yields in Pb–Pb interactions at 158 GeV/c per nucleon are presented as a function of the collision centrality. The possible onset of a deconfined phase when the collision involves from 50 to 100 wounded nucleons is discussed.

The Silicon Pixel Detector for ALICE Experiment

The Inner Tracking System (ITS) of the ALICE experiment is made of position sensitive detectors which have to operate in a region where the track density may be as high as 50 tracks/cm2. To handle such densities detectors with high precision and granularity are mandatory. The Silicon Pixel Detector (SPD), the innermost part of the ITS, has been designed to provide tracking information close to primary interaction point. The assembly of the entire SPD has been completed.

Strange Baryon Production from the NA57 Experiment at the CERN SPS

The production of strange baryons and anti‐baryons in PbPb and pBe collisions has been studied by the NA57 experiment at the CERN SPS, extending down the centrality range covered by the previous WA97 experiment, and collecting data at two different energies. The enhanced production of such particles in central PbPb collisions with respect to pBe has been experimentally confirmed. This paper discusses results on Ⅺ and Λ hyperon production obtained at 40 and 158 A GeV/c.