John W. Harris

Introduction The primary motivation for studying relativistic heavy ion collisions is to gain an understanding of the equation of state of nuclear, hadronic and partonic matter, commonly referred to as nuclear matter. This endeavor is of cross-disciplinary interest to nuclear physics, astrophysics, cosmology and particle physics. Fig. 1. Schematic phase diagram of nuclear matter. Displayed in Fig. 1 is a schematic phase diagram of nuclear matter. The behavior of nuclear matter as a function of temperature and density (or pressure), shown in Fig. 1, is governed by its equation of state. Conventional nuclear physics is concerned primarily with the lower left portion of the diagram at low temperatures and near normal nuclear matter density. Here normal nuclei exist and at low excitation a liquid-gas phase transition is expected to occur. This is the focus of experimental studies using low energy heavy ions. At somewhat higher excitation, nucleons are Czec