Studies of Heavy Pear-shaped Nuclei

Abstract

For certain combinations of protons and neutrons it is expected that the shape of atomic nuclei can undergo octupole deformation, which would give rise to reflection asymmetry or a “pear shape”. Here it is described how recent experiments carried out at CERN using REX-ISOLDE and HIE-ISOLDE and the Miniball gamma-ray spectrometer have provided evidence that several radium and radon isotopes have either stable pear shapes or are octupole vibrational in nature. It will be shown that the data on transition moments present some challenges for theory. The relevance of these measurements for atomic EDM searches, and the future prospects for this field, will also be discussed.

Studies of reflection asymmetry in heavy nuclei

“…Prior to the present work experimental signatures in heavy nuclei have been observed for only two cases, 224 Ra [3] and 226 Ra [4]. This paper summarises new information on energy levels and electric matrix elements for the radioactive isotopes 222,224,226 Rn (Z = 86) and 222,228 Ra (Z = 88) obtained from recent experiments using the HIE-ISOLDE facility at CERN (for a brief review, see [5]). The behaviour of nuclei with A ≈ 220 is compared here with that of isotopes with Z ≈ 58, A ≈ 150.…”