Nuclear Collective Motion

The two most important developments in nuclear physics were the shell model and the collective model. The former gives the formal framework for a description of nuclei in terms of interacting neutrons and protons. The latter provides a very physical but phenomenological framework for interpreting the observed properties of nuclei. A third approach, based on variational and mean-field methods, brings these two perspectives together in terms of the so-called unified models. Together, these three approaches provide the foundations on which nuclear physics is based. They need to be understood by everyone practicing or teaching nuclear physics, and all those who wish to gain an understanding of the foundations of the models and their relationships to microscopic theory as given by recent developments in terms of dynamical symmetries. This book provides a simple presentation of the models and theory of nuclear collective structure, with an emphasis on the physical content and the ways they are used to interpret data. Part 1 presents the basic phenomenological collective vibrational and rotational models as introduced by Bohr and Mottelson and their many colleagues. It also describes the extensions of these models to parallel unified models in which neutrons and protons move in a mean-field with collective degrees of freedom. Part 2 presents the predominant theories used to describe the collective properties of nuclei in terms of interacting nucleons. These theories, which are shared with other many-body systems, are shown to emerge naturally from the unified models of Part 1.

The scope of the international meeting covered a broad range of the recent developments in nuclear physics, from heavy-ion collisions from Coulomb barrier through relativisitc energies (using stable and radioactive beams), to some applications of nuclear physics and other research fields. The lectures given at the meeting range from the most recent progress to future prospects in nuclear physics research.This volume focuses on recent developments in nuclear physics, with emphasis on the investigation of processes connected with large-amplitude collective motion in nuclei, such as heavy-ion fusion, giant multipole resonances, and nuclear fission and fragmentation.

These proceedings contain selected topics covering various fields of collective motion and nuclear dynamics, ranging from low to high energies, from nuclear structure to reaction mechanisms, from regular stable to chaotic systems, and from fragmentation to fusion. Several ways of investigating the nuclear systems are presented: electron scattering radioactive beams, fragmenting projectiles, beta and double beta decays, and cluster emission. Their behaviour, under some extreme situations such as superdeformation, high spin states, high temperature, and relativisitic energy, is described within various theoretical formalisms.

The RIKEN Symposium was held in December of 1989 with 3 main goals in mind. The first goal was to survey the present status of studies in nuclear collective motion and nuclear reaction dynamics. The second goal was to look into future directions of the two topics. The third goal of the Symposium was to commemorate the work of the late Professor Taro Tamura.

The proceedings of the symposium on Nuclear Collective Motion and Nuclear Reaction Dynamics is dedicated to three main areas: to survey the present state of studies in nuclear collective motion and nuclear reaction dynamics, to study the possible future directions of these two topics and to commemorate the work of the late Taro Tamura.

The two most important developments in nuclear physics were the shell model and the collective model. The former gives the formal framework for a description of nuclei in terms of interacting neutrons and protons. The latter provides a very physical but phenomenological framework for interpreting the observed properties of nuclei. A third approach, based on variational and mean-field methods, brings these two perspectives together in terms of the so-called unified models. Together, these three approaches provide the foundations on which nuclear physics is based. They need to be understood by everyone practicing or teaching nuclear physics, and all those who wish to gain an understanding of the foundations of the models and their relationships to microscopic theory as given by recent developments in terms of dynamical symmetries.This book provides a simple presentation of the models and theory of nuclear collective structure, with an emphasis on the physical content and the ways they are used to interpret data. Part 1 presents the basic phenomenological collective vibrational and rotational models as introduced by Bohr and Mottelson and their many colleagues. It also describes the extensions of these models to parallel unified models in which neutrons and protons move in a mean-field with collective degrees of freedom. Part 2 presents the predominant theories used to describe the collective properties of nuclei in terms of interacting nucleons. These theories, which are shared with other many-body systems, are shown to emerge naturally from the unified models of Part 1.