Shape Changes in the Mirror Nuclei 70Kr and 70Se

We studied the proton-rich T-z = -1 nucleus Kr-70 through inelastic scattering at intermediate energies in order to extract the reduced transition probability, B(E2; 0+ -> 2+). Comparison with the other members of the A = 70 isospin triplet, Br-70 and Se-70, studied in the same experiment, shows a 3 sigma deviation from the expected linearity of the electromagnetic matrix elements as a function of T-z. At present, no established nuclear structure theory can describe this observed deviation quantitatively. This is the first violation of isospin symmetry at this level observed in the transition matrix elements. A heuristic approach may explain the anomaly by a shape change between the mirror nuclei Kr-70 and Se-70 contrary to the model predictions.

Automated summary

Study of the proton-rich T-z = -1 nucleus Kr-70 through inelastic scattering reveals a deviation in the electromagnetic matrix elements compared to other isotopes Br-70 and Se-70, suggesting a violation of isospin symmetry at this level not previously observed. Current nuclear structure theories are unable to quantitatively explain this anomaly, possibly indicating a shape change between Kr-70 and Se-70 contrary to model predictions.