Ultrarelativistic Heavy-Ion Collisions and the Properties of Nuclear Matter Under Extreme Conditions

Abstract

The two main issues I will discuss in these lectures are the nature of extended nuclear matter at extremely high energy densities, and how, by means of ultrarelativistic heavy-ion collisions in the laboratory, one can create matter at high densities, and thus have the opportunity to learn about its properties experimentally. To set the scale of nuclear energy densities let us note that the total energy in a nucleus in its ground state is essentially the rest mass density of the nucleons. Since nuclear matter has a density ρnmof order 0.16 nucleons/fm ³ and the nuclear mass is of order 940 MeV, the rest mass density is of order 0.15 Gev/fm ³. This energy density is large compared with the scale of low-energy spectroscopy, involving energy densities of order Mev/fm³. The question we are interested in is how we expect nuclear matter to act when we raise its energy density to the range of 1 — 10 Gev/fm ³ say. What, for example, are its principal degrees of freedom, its thermodynamic properties, and its quantum chromodynamic properties?

Supported in part by NSF Grant PHY84-15064.