Dynamic and static axial symmetry breaking in nuclei

Sammanfattning

In the collective model of the atomic nucleus, oscillations in the quadrupole deformation naturally arise; a type of these dynamic shape fluctuations are known as γ-vibrations. However, features attributed to these vibrational modes may instead arise from static triaxiality through configuration mixing. This thesis explores a possible way to avoid this ambiguity. Whilst single phonon γ-vibrations are firmly established the search for pure double phonon γγ-vibrations is currently underway. And thus, a good theoretical understanding of γ-vibrations would be beneficial. The central idea of this work is to suppress the rotational copies of the intrinsic shape by restricting the rotational degree of freedom to a single axis in the nuclear model. Two nuclei, 24Mg and 32S, were investigated and both showed behaviour characteristic of γ-vibrational modes. The results furthermore agree closely with the Bohr Hamiltonian thus affirming the interpretation of γ-vibrations as true dynamic shape fluctuations.