Yrast band in the heavy $N = Z$ nucleus $^{88}$Ru: $\alpha$-cluster approach

Abstract

The yrast band in the heavy $N = Z$ nucleus $^{88}$Ru is studied in the framework of the $\alpha$-cluster model in combination with double-folding potentials. It is found that the excitation energies of the yrast band in $^{88}$Ru can be nicely described within the $\alpha$-cluster approach using a smooth and mildly $L$-dependent adjustment of the potential strength. This result is similar to well-established $\alpha$-cluster states in nuclei with a (magic core $\otimes$ $\alpha$) structure. Contrary, the yrast bands in neighboring $N \ne Z$ nuclei deviate from such a typical $\alpha$-cluster behavior. Finally, the $\alpha$-cluster model predicts reduced transition strengths of about 10 Weisskopf units for intraband transitions between low-lying states in the yrast band of $^{88}$Ru.