Speaker
Description
The sudden onset of deformation in $A\approx100$ nuclei at $N=60$ has been described as a ground-state shape transition that has raised a lot of interest over the years from an experimental and theoretical point of view. This transition is most pronounced in the Zr and Sr isotopic chains where the low-energy excited-state structure shows significant signs of deformation developing at $N=60$, as opposed to the spherical-like structure observed at $N\leq58$.
At present, the two most promising theoretical interpretations of this phenomenon are given by the Monte Carlo Shell Model (MCSM) and the Interacting Boson Model with Configuration Mixing (IBM-CM). The MCSM calculations interpret the structure of $^{100}$Zr within a multiple-shape-coexistence scenario with several distinct deformed shapes predicted for the lowest $0^+$ states, with rotational bands built on top of them. In contrast, the IBM-CM calculations predict a weakly-deformed ''intruder'' ground-state configuration in $^{100}$Zr, with corresponding $\beta$ and $\gamma$ bands, and a low-lying spherical ''normal'' configuration.
In order to test these theoretical models an experiment was performed at Canada's national particle accelerator centre TRIUMF to investigate the structure of $^{100}$Zr following the $\beta$ decay of $^{100}$Y by utilizing the $\gamma$-ray spectrometer GRIFFIN (Gamma Ray Infrastructure For Fundamental Investigations of Nuclei). The 15 hyper-pure Ge clover detectors of GRIFFIN were coupled with seven lanthanum bromide detectors for fast-timing lifetime measurements using the Generalized Centroid Difference method.
The lifetimes of several key excited states in $^{100}$Zr, extracted for the first time in this study, will be compared to the MCSM and IBM-CM theoretical predictions. Evidence supporting the shape-coexistence scenario in $^{100}$Zr will be presented, together with the notable structural similarities between $^{100}$Zr and $^{98}$Sr.
| Your current academic level | Postdoctoral researcher |
|---|---|
| Your email address | kstoyche@uoguelph.ca |
| Affiliation | University of Guelph |
| Supervisor name | Paul Garrett, Carl Svensson |
| Supervisor email | garrettp@uoguelph.ca |
