Centrality Dependence of Thermal Parameters in Heavy-Ion Collisions at Relativistic Energies

The centrality dependence of thermal parameters, characterizing the hadron multiplicities, is determined phenomenologically
for lead-on-lead collisions at CERN-SPS for a beam energy of 158 A GeV.
The strangeness equilibration factor shows a clear, approximately linear, increase with increasing centrality, while the freeze-out temperature and chemical potential remain constant.