This thesis presents significant new observations of nuclear wobbling, and thus expands our understanding of nuclear triaxiality and its prevalence in the nuclear chart. Triaxial nuclear shapes are a very rare phenomena and their experimental identification often relies on two unique signatures nuclear wobbling motion and chiral rotation. While nuclear chirality is a well-studied phenomenon, experimental observations of wobbling nuclei are rather limited. With the identification of 135Pr and 187Au as wobblers, this work establishes triaxiality to be a general phenomenon present in different regions of the nuclear chart, irrespective of any particular spin or deformation. A major focus of this work is the detailed investigation of the different kinds of wobbling modes. Depending on the geometry of the nuclear system, wobbling can be classified into two types longitudinal and transverse. This work has, for the first time, reported evidence of the possible coexistence of both forms of wobbling in a single nucleus. Another important result reported in this work is the very first observation of co-existing chiral and wobbling modes in the 135Pr nucleus. This thesis details the experimental methods that led to this breakthrough, along with pertinent theoretical interpretations.

This thesis presents significant new observations of nuclear wobbling, and thus expands our understanding of nuclear triaxiality and its prevalence in the nuclear chart. Triaxial nuclear shapes are a very rare phenomena and their experimental identification often relies on two unique signatures – nuclear wobbling motion and chiral rotation. While nuclear chirality is a well-studied phenomenon, experimental observations of wobbling nuclei are rather limited. With the identification of 135Pr and 187Au as wobblers, this work establishes triaxiality to be a general phenomenon present in different regions of the nuclear chart, irrespective of any particular spin or deformation. A major focus of this work is the detailed investigation of the different kinds of wobbling modes. Depending on the geometry of the nuclear system, wobbling can be classified into two types – longitudinal and transverse. This work has, for the first time, reported evidence of the possible coexistence of both forms of wobbling in a single nucleus. Another important result reported in this work is the very first observation of co-existing chiral and wobbling modes in the 135Pr nucleus. This thesis details the experimental methods that led to this breakthrough, along with pertinent theoretical interpretations.

The book provides an introduction to both theoretical and experimental results on chirality and wobbling in atomic nuclei. It details the achievements in the study of chirality over the past 25 years since the first prediction of this mode of collective motion in nuclei, as well as those on the wobbling motion. It offers a detailed review of the most relevant theoretical developments on both types of collective motion and the experimental results supporting or not the theoretical predictions. Different views on wobbling are included and confronted with the contradicting experimental results on low-spin wobbling. It is intended to foster further research on these types of exotic collective motion in nuclei. Which and how these exotic collective motions occur in nuclei, which are their predicted fingerprints and how they are supported by the experimental facts will be presented. Polemics, debates, and ambiguities in the interpretation of the experimental results will be exposed. The reader will have the opportunity to have together different views on the two phenomena that animated the scientific activity in low-energy nuclear physics in many laboratories around the world. The book will be a valuable reference for PhD students, post-docs and researchers in addition to universities and research institutions. Key Features: - The first book on chirality and wobbling in nuclei. - Contains a comprehensive review of topics related to chirality and wobbling, including both theoretical and experimental aspects. - Contains chapters from leading researchers in the field.

In recent years, a new field of nuclear research has been opened through the possibility of studying nuclei wi\h very large values of angular momentum, temperature, pressure and number of particles. This development has been closely associated with heavy ion reactions, since collisions between two heavy nuclei are especially effective in producing metastable compound systems with large angular momentum, and in transferring energy which is distributed over the whole nuclear volume. Under the strain of temperature and of the Coriolis and centrifugal forces, the nucleus displays structural changes which can be interpreted in terms of pairing and shape phase transit ions. This was the subject of the lectures of J. D. Garrett, P. J. Twin and S. Levit. While the rotational motion is, at zero temperature un damped, the width of giant resonances indicate that the nucleus only oscillates through few periods before the motion is damp ed by particle decay, and through coupling to the compound nucleus. Temperature and angular momentum influence in an im portant way the properties of both giant resonances and rotatio nal motion. These subjects were developed by K. Snover, and by P. F. Bortignon and R. A. Broglia, as well as by A. Bracco, A. Dellafiore and F. Matera.