Hot and Dense Nuclear  From Nucleus to Nucleon  The dynamics of nuclear

How to proceed

A much clearer picture of this physics is emerging now and a strong experimental and theoretical program lies ahead.

Detectors

• Some of the open questions (role of compression, finite size effects, nuclear friction) will be addressed by programs making use of the existing $\pi$ detectors and by those under construction and modification.

Two main axes of questions have to be developed in the future : one is to achieve a proper measurement and understanding of temperatures and the second is to obtain time-dependent information on the dynamics of the reaction and on the fragment formation process. A step towards the first goal should be achieved via a more precise measurement of isotope ratios and excited state populations. This requires the development of detectors with unit mass resolution for nuclei up to Z=20. A joint European program to manufacture these and to use them in a variety of experiments such as is the case presently for neutron and gamma detectors should be considered. The second goal is more ambitious. Interesting time dependent signals have been obtained via the study of high energy gamma rays produced by Bremsstrahlung processes. This would involve the coupling of charged particle and gamma detectors with large efficiencies. Such a project is already developed in Italy, and an extension of this could be considered and driven by a European collaborative effort. A more distant possibility is offered by the future availability of radioactive beams. The variation of the overall isospin ratio as well as the respective isospin ratio of the projectile, target and of the neck between them, opens up a new dimension in the study of nuclear matter. For this subject to develop, a significant theoretical effort must be undertaken in order to extract and define those signals that will carry the information after the cooling of the system. If this is warranted, a third generation of detectors may be called for.

Accelerators
This program makes use of the wide variety of beams and energies provided at European laboratories in France, Germany, Italy, the Netherlands, Sweden, and at CERN.

• An important condition for the success of this field is the continued and easy access to the beams delivered by these institutions.

Theory
A more precise description and understanding of these collisions requires a sustained effort and significant manpower. The investment made into the development of efficient detectors can only be fully exploited if it has its counterpart in the domain of theory. As an example, the necessary quantitative comparison between experimental data and model generated events requires the latter to be increased by several orders of magnitudes. Another necessary development is an improved implementation of quantum effects, of fluctuations and of finite size effects into the dynamical codes.

• A sustained effort in the development of theoretical models must accompany the incoming flux and analysis of experimental data. Besides sufficient manpower this also requires adequate computational infrastructure for the theoretical groups.