Cu*

Exotic nuclei with excess neutrons relative to stable ones often exhibit evolved shell structure and collectivity such as vibrated/deformed shapes, which compete with each other to express the actual structure. Here we show the precision analysis of this competition by focusing on the magnetic moment of an isomeric state of a neutron-rich nucleus ⁷⁵Cu, where an intriguing shell evolution has been reported.

The magnetic moment measurement was carried out at RIKEN RIBF, taking advantage of a spin-aligned RI beam produced with the two-step projectile fragmentation scheme recently proposed. The spin alignment as large as 30% was achieved by the two-step scheme incorporating an angular-momentum selecting proton removal from ⁷⁶Zn to produce ⁷⁵Cu. The magnetic moment of the isomeric state of ⁷⁵Cu was determined by means of TDPAD method.

In this talk, the experimental results will be presented. Discussion on the above competition at neutron-rich Cu isotopes, analyzed with the Monte-Carlo shell model calculation, will also be given.