Structure of the neutron-rich nucleus ${}^{30}\mathrm{Mg}$, which is located close to the region of the $N=20$ “island of inversion,” has been investigated by $\beta \text{−}\gamma$ spectroscopy of spin-polarized ${}^{30}\mathrm{Na}$. From the detailed $\gamma \text{−}\gamma$ coincidence relations, nine new states have been established in ${}^{30}\mathrm{Mg}$. The spin-polarization of ${}^{30}\mathrm{Na}$ enabled firm spin-parity assignments for seven states in ${}^{30}\mathrm{Mg}$ by means of the spatial asymmetry of $\beta$-ray counts in coincidence with the ${}^{30}\mathrm{Mg}\gamma$ rays. Based on the experimental information, it is shown that various characteristic structures coexist in ${}^{30}\mathrm{Mg}$: (i) the ground-state vibrational-like band, (ii) the deformed band built on the $0_2^{+}$ state at 1.788 MeV, (iii) the $\gamma$-vibrational band built on the $2_3^{+}$ state at 3.543 MeV, and (iv) four states around 5 MeV associated with large $\beta$-transition probabilities: $1^{+}$ and $2^{+}$ states with spherical nature, $1^{+}$ and $2^{+}$ states with collective nature. The experimental results are compared with three theoretical calculations of the CHFB $+$ LQRPA, the AMD $+$ GCM, and the large-scale shell model with the EEdf1 interaction. All these theories reasonably reproduce the three bands.

中文翻译：

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富中子核Mg30的结构

富中子核的结构 ${}^{30}镁$，其位置靠近 $ñ=20$ “反演之岛”已经被 $\beta \text{-}\gamma$ 自旋极化光谱 ${}^{30}娜$。从详细$\gamma \text{-}\gamma$ 巧合关系，在美国建立了九个新州 ${}^{30}镁$。的自旋极化${}^{30}娜$ 在以下七个州启用了公司自旋奇偶校验分配 ${}^{30}镁$ 通过空间不对称 $\beta$射线计数与 ${}^{30}镁\gamma$射线。根据实验信息，表明各种特征结构共存。${}^{30}镁$：（i）类基态振动带，（ii）建立在基带上的变形带 $0_2^{+}$ 状态为1.788 MeV，（iii） $\gamma$-建立在 $2_3^{+}$ 状态为3.543 MeV，并且（iv）大约5 MeV的四个状态与大 $\beta$-转移概率： ${\mathrm{1个}}^{+}$ 和 $2^{+}$ 具有球形性质的状态 ${\mathrm{1个}}^{+}$ 和 $2^{+}$具有集体性质的国家。将实验结果与CHFB的三个理论计算进行了比较 $+$ LQRPA，AMD $+$ GCM，以及与EEdf1交互的大型外壳模型。所有这些理论都合理地再现了这三个频段。