  The evolution of charged-particle production in collisions of heavy ions at
relativistic energies is investigated as function of centrality in a
nonequilibrium-statistical framework. Precise agreement with recent d + Au and
Au + Au data at sqrt(s_NN) = 200 GeV is found in a Relativistic Diffusion Model
with three sources for particle production. Only the midrapidity source comes
very close to local equilibrium, whereas the analyses of the overall
pseudorapidity distributions show that the systems remain far from statistical
equilibrium.
