Search

A γ - γ coincidence Recoil Distance Doppler-Shift measurement has been carried out on 60 Ni to re-measure the lifetime of the 2 1 + and 4 1 + states. The new lifetime of the 2 1 + state supports the adopted NNDC value but disagrees with the results of two more recent Doppler-Shift Attenuation Method measurements, which suggested a longer lifetime. The new result for the 4 1 + state's lifetime is significantly shorter than the one recommended in the latest NNDC compilation while also reducing its uncertainty. It therefore resolves an unclear situation, where an unexpected drop in transition strength appeared from 58 Ni to 60 Ni. Both values match very well with recently applied shell model calculations using the GXPF1A interaction. [ABSTRACT FROM AUTHOR]

In this analysis, the energy spectrum of -rays coincident with one particular transition is generated by requiring that the energy of this gating transition lies in a specific range. Each spectrum corresponds to a particular gating transition, background subtracted, so that the peaks observed in the spectrum arise from -ray transitions in coincidence with that transition. For octupole vibrational nuclei in which the negative-parity states arise from coupling an octupole phonon to the positive-parity states, it is expected that HT ht as the phonon prefers to align with the rotational axis. [Extracted from the article]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

There is a large body of evidence that atomic nuclei can undergo octupole distortion and assume the shape of a pear. This phenomenon is important for measurements of electric-dipole moments of atoms, which would indicate CP violation and hence probe physics beyond the Standard Model of particle physics. Isotopes of both radon and radium have been identified as candidates for such measurements. Here, we observed the low-lying quantum states in 224Rn and 226Rn by accelerating beams of these radioactive nuclei. We show that radon isotopes undergo octupole vibrations but do not possess static pear-shapes in their ground states. We conclude that radon atoms provide less favourable conditions for the enhancement of a measurable atomic electric-dipole moment. Octupole deformation in nuclei is important to understand nuclear structure and electric dipole moments of heavy atoms. Here the authors measure energies of excited quantum states in radon isotopes and find that these isotopes do not provide favourable conditions in the search for CP-violation. [ABSTRACT FROM AUTHOR]