Speaker
Description
Theoretical models often invoke triaxial nuclear shapes to explain elusive collective phenomena, but such assumptions are usually difficult to confirm experimentally. The only direct measurements of the nuclear axial asymmetry $\gamma$ is based on rotational invariants of zero-coupled products of the electric-quadrupole (E2) operator, which generally require knowledge of a large number of E2 matrix elements connecting the state of interest. We propose an alternative method to determine $\gamma$ of even-even deformed nuclei using ratios of two E2 matrix elements only, which are typically well known. While this approach is based on modelling the rotation of a rigid triaxial nucleus following the Davidov and Filippov model, it is applied in such a way that it becomes practically model-independent and parameter-free. The results are in agreement with the Kumar-Cline model-independent values of $\gamma$ (where measurements are available). The technique was applied to more than 60 deformed even-even nuclei suggesting that deformed nuclei generally exhibit well-defined axially-asymmetric shapes rather than deformation softness as it is commonly presumed.
