Results on strangeness production from the NA57 experiment

Abstract

A review of recent NA57 results on K0S and hyperon production from Pb–Pb collisions at 40 and 158 A GeV/c is presented. An energy and centrality dependence of particle yields, strangeness enhancements as well as transverse mass spectra at mid-rapidity are discussed.

K0S, Λ and measurements from 62.4 GeV Au+Au collisions in STAR

“…The ratio for each particle was normalized to the value of the most peripheral bin in each curve. These data seem to show the same strangeness enhancement pattern observed by SPS experiments [2], but with an earlier saturation point.…”

“…Strange particle production is an important observable in relativistic heavy-ion collisions that can provide unique and essential information on the physical environment created in the collision. Kaons and lambdas make up the bulk of strange particles produced; thus, they have been extensively measured from the AGS [1] to SPS experiments [2] and in more recent years at RHIC [3][4][5]. In 2003, STAR has recorded Au+Au collisions at a nucleus-nucleus centre-of-mass energy of √ s NN = 62.…”

Overview of strangeness production at the CERN SPS

“…The NA57 experiment confirmed the WA97 results and extended the measurements to a wider centrality region and lower energy (40 A GeV) [6,22,23]. An access to the wider centrality range allowed us to observe a significant centrality dependence of the Pb-Pb yields per participant for all hyperons except for .…”

Strangeness at RHIC: recent results from STAR

“…The details of the thermal freeze-out temperatures and radial expansion velocities resulting from a blastwave parametrization are explained elsewhere in these proceedings [8]. Recent results from NA49 and NA57 presented at this conference [16,17] confirm that the fit quality improves if one assumes different freeze-out properties for multi-strange baryons. Still a hydrodynamical fit, assuming a QGP equation of state, also yields good fit quality with a common hadronic freeze-out surface for all particles.…”