CERN Accelerating science

For certain combinations of protons and neutrons, there is a theoretical expectation that the shape of nuclei can assume octupole deformation,
which would give rise to reflection asymmetry or a “pear shape” in the
intrinsic frame, either dynamically (octupole vibrations) or statically (permanent octupole deformation). In this paper, I will briefly review the
historic evidence for reflection asymmetry in nuclei, describe how recent
experiments carried out at REX-ISOLDE are constraining nuclear theory
and how they contribute to tests of extensions of the Standard Model, and
look at future prospects for this field.