Speaker: Maciej Lewicki

Title: “Strangeness production and the onset of fireball at NA61/SHINE”

Abstract:
NA61/SHINE is a fixed target experiment at the CERN Super Proton Synchrotron. The experiment studies the properties of strongly interacting matter in the vicinity of the onset of deconfinment through collisions of ions, varying both the collision energy and the size of colliding nuclei. The most recent analyses of hadron production in ^{40}Ar+^{45}Sc and ^{7}Be+^{9}Be interactions deliver some puzzling results concerning the system size dependence of strangeness production, which cannot be reproduced by theoretical models. The pronounced differences of charged kaon production properties in small (p+p and Be+Be) and large (Ar+Sc and Pb+Pb) systems can be interpreted as a signature of the "onset of fireball" - a beginning of creation of large clusters from binary collisions of nucleons.
In this talk, I will review key results from Ar+Sc and Be+Be collisions at beam momenta 19A-150A GeV/c in the context of possible signatures of both described onsets.