Soft Physics, Centrality and Multiplicity at RHIC

Abstract

The inclusive spectra so far accumulated at the Relativistic Heavy Ion Collider (RHIC) at energies of $\sqrt{s} = 56, 130$ and 200 GeV are examined within the hadronic simulation LUCIFER. What emerges at this juncture is a comprehensive and clear picture of soft physics which apparently dominates the intermediate and later stages of the ion collisions. The focus is on energy and centrality dependence of the mid-rapidity charged spectra, using an analysis based for the most part on production and rescattering of intermediate generic resonances. The bosonic Rho and K(*)-like resonances, produced in initial nucleon-nucleon interactions and materialising only after some delay time, behave like an incompressible fluid with saturated number and energy density.