Background: The experimental study of $g(I>2)$ factors of nuclear states can provide information about the evolution of collectivity in certain regions of the nuclear chart, and assist in obtaining a microscopic description of the nuclear wave functions. The measurements and explanations of $g(I>2)$ factors are still a challenge for experiments and theory.

Purpose: Measurement of the $g\left(2_1^{+}\right)$ and $g\left(4_1^{+}\right)$ factors, the latter for the first time, in the ${}_{44}^{96}$Ru nucleus. Comparison of the experimental results with calculations using the shell model and collective models.

Methods: The experiments made use of the transient field technique, using a Coulomb-excitation reaction in inverse kinematics. Large scale shell model calculations were performed; comparisons with previous theoretical predictions, using the tidal-wave model and the hydrodynamical model, were carried out.

Results: The values of $g\left(2_1^{+}\right)=+0.46\left(2\right)$ and $g\left(4_1^{+}\right)=+0.58\left(8\right)$ were experimentally obtained. While the $g\left(2_1^{+}\right)$ value agrees with the hydrodynamical model prediction of $g=Z/A=+0.46$, the $g\left(4_1^{+}\right)$ is in agreement with the shell model predictions. The trend of the experimental $g$ factors, as a function of nuclear spin, is not reproduced by the theoretical models discussed.

Conclusions: Measurements of $g\left(2_1^{+}\right)$ and $g\left(4_1^{+}\right)$ in ${}^{96}$Ru were performed. Further theoretical efforts are necessary to explain the trend of the $g$ factors as a function of nuclear spin for the ${}^{96}$Ru nucleus. Future measurements of $g\left(4_1^{+}\right)$ should reduce the uncertainty of the result.

• Received 16 December 2011

DOI:https://doi.org/10.1103/PhysRevC.85.017305