Preface

We derive an exact gauge covariant equation of motion for the SU(N) quantum chromodynamic Wigner operator. That equation naturally splits up into an on-shell constraint equation and a transport equation. In the semiclassical limit the transport equation reduces to a Vlasov type equation with non-abelian and spin-dependent terms. We show how quantum corrections can be calculated systematically. Under suitable conditions the transport equations reduces to a particularly simple set of abelian equations in the Cartan basis of SU(N).

In this report, the relevance and possible manifestations of quark-gluon degrees of freedom in nuclear systems are discussed. An attempt is made to view the subject in the context of the modern theory of fundamental interactions based on the concept of local gauge invariance. How this gives rise to the quantum chromodynamics of colored quarks and gluons is recounted. An introduction is given to the concepts of asymptotic freedom, color confinement, lattice gauge theory, and chiral symmetry. The nature, the successes and limitations of phenomenological quark models of hadrons are described. The possible appearance of exotic hadrons, and of quark effects in nuclear forces, in high-energy nuclear reactions and in nuclear properties are discussed. The expected properties and possible production and detection of unusual quark-gluon phases of matter are reviewed. Both the experimental detection and the theoretical treatment of quark effects in nuclei appear difficult, but the question of how nuclear physics fits into the panorama which is the modern theory of fundamental interactions appears to represent a worthwhile intellectual challenge.

The first results from a high energy accelerator ion experiment (CERN EMU05), and a comparative summary of high and ultra-high energy cosmic ray (JACEE) results, are presented. The EMU05 data on the multiplicity distribution for 200 GeV/amu ¹⁶O+Pb collisions is consistent with a Glauber-scheme calculation and the JACEE results. Close hadronic-pairs observed by EMU05 are as abundant as the JACEE data, suggesting a freeze-out source radius of 2.5–3.0 fm. The central pseudo-rapidity density of typical central collisions (200 GeV, ¹⁶O+Pb) is about 100 per unit, which implies the energy density less than ∼1.5GeV/fm³, below that of the highest energy-density JACEE events.