SESZIONE DI TORINO
Global strangeness production in relativistic heavy ion collisions from 5 to 200 GeV centre-of-mass energy is reviewed. Enhanced strangeness production in heavy ion collisions with respect to proton-proton collisions was early proposed as a signature of the formation of Quark-Gluon Plasma. While the enhancement has actually been observed, its interpretation as signature has been questioned and the attention has focussed on the possible achievement of full chemical equilibrium, an issue which has also been subject of debate. In this seminar I will review the status of our knowledge and understanding of strangeness production in heavy ion collisions and will discuss a recent advance coming from measurements of strangeness production as a function of centrality of collisions, showing that the data is consistent with a superposition of particle emission from an equilibrated hadron gas in the core and single independent nucleon-nucleon collisions in the boundary of the reaction region, the corona.

DATA: 10-12-2008