Search

The last decade has been witness to many exciting and rapid developments in the fields of Nuclear Physics and Intermediate Energy Physics, the interface between Nuclear and Elementary Particle Physics. These developments involved to a large extent the sub nucleonic degrees of freedom in nuclei. In deep inelastic lepton scattering from nuclei, for example, it was observed that the quark structure of the nucleon is influenced by the nuclear medium. Also, the spin-dependent structure function of the nucleon was found to differ from sum rules based on SU(3) symmetry, a discrepancy referred to as the'spin crisis'. In pion electroproduction at threshold and in the production of pions and other mesons in heavy ion collisions at intermediate energies interesting experimental results have been obtained, which triggered lively theoretical discussions. Furthermore, the search for the quark-gluon plasma phase of hadronic matter, a phase that is supposed to have existed in the first few seconds of the Big Bang, has been intensified. Not only were these developments accompanied by technical developments, such as the building of new experimental facilities, but also extensive theoretical efforts have been directed towards understanding these phenomena. These concerted efforts will hopefully lead to an understanding of the transition from the non-perturbative QCD regime to the perturbative one, in which the quark structure of nucleons is better understood. All of the aforementioned developments occur at a high pace, making it difficult to incorporate them into the courses offered to advanced students.

Particle production is an important topic in nuclear and particle physics. At high energies, particle production is considered to proceed via parton branching and subsequent fragmentation into hadrons. The study of the dynamics of this process and the study of the structure of hadrons in the context of quantum chromodynamics (QCD) belong to the challenges of the standard model of elementary particle physics, requiring new, nonperturba­ tive approaches in field theory. Within a nucleus, many-body dynamics is important and particle production may be used to determine many features of a non-equilibrium quantum system at low or high temperatures. At this Advanced Study Institute the different aspects of particle pro­ duction were expanded upon in a series of lectures given by experts in their fields, covering topics ranging from near-threshold meson production in proton-proton collisions to correlations in multi-GeV jet fragmentation in high-energy scattering processes and signals of a quark-gluon plasma formed in ultra-relativistic heavy-ion collisions. Strong emphasis was placed not only on state of the art research, but also on the necessary physics back­ ground. The lectures were supplemented by problem sets and discussion sessions. There was also time for students to present short contributions on their research.

In many areas of physics, such as astrophysics, solid-state physics, nuclear physics and particle physics, a major outstanding problem is a better understanding of corre­ lation phenomena. While in most cases the average properties of a system are rather well understood, the correlations and the resulting clustering are poorly understood. They are reflections of the force mediating the interaction among the constituents and play essential roles in determining the structure of a physical system. At the largest scales, in astrophysics, it has recently been realized that there are huge voids in space and almost all matter is concentrated on filaments, raising interesting questions concerning the origin of this clustering of matter. In nuclear physics corre­ lation phenomena are important in all its subfields. It has been realized that so-called fluctuations in the one-particle density, which are a manifestation of nucleon-nucleon correlations, are crucial. These are important for an understanding of heavy-ion reac­ tions. This is the subject of modern quantum transport theories. Correlations are also crucial in the description of the high momentum components as observed in quasi-elastic knock-out reactions.