Structure of Mg30 explored via in-beam γ-ray spectroscopy
Structure of Mg30 explored via in-beam γ-ray spectroscopy
复制标题
通过束内 γ 射线光谱探索 Mg30 的结构
DOI：
10.1103/physrevc.102.054318
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发表时间：
2020
影响因子：
3.1
通讯作者：
Utsuno Y. et al.
中科院分区：
文献类型：
--
作者：
Kitamura N.;Wimmer K.;Shimizu N.;Utsuno Y. et al.
背景：在“反转岛”中，富中子壳核的基态表现出来自壳层的强侵入体构型的混合。该核位于逆温岛的边界，当人们接近该区域时，它是跟踪构造演化的基石。目的：激发态的自旋宇称赋值，特别是负宇称水平，尚未建立。在目前的工作中，用束内射线光谱学研究了核结构，主要集中在确定自旋宇称。方法：用高强度的稀有同位素束轰击Be靶，诱导填充态的核子去除反应。射线被最先进的射线跟踪阵列GRETINA探测到。对于直接的单中子去除反应，推导出了末态独占截面和平行动量分布。利用不同抛射体的多核去除反应来获得互补信息。结果：利用平行动量分布，构造了一个修正自旋宇称赋值的能级格式。并推导出与每种状态相关的光谱因子。结论：结果与使用两种不同有效相互作用的大尺度壳模型计算相冲突，显示出与当前水平方案的良好一致性。然而，光谱因子的显著差异表明，全面描述向反演岛的过渡仍然是理论模型的一个挑战。
Background:In the “island of inversion,” ground states of neutron-rich-shell nuclei exhibit strong admixtures of intruder configurations from theshell. The nucleus, located at the boundary of the island of inversion, serves as a cornerstone to track the structural evolution as one approaches this region.Purpose:Spin-parity assignments for excited states in, especially negative-parity levels, have yet to be established. In the present work, the nuclear structure ofwas investigated by in-beam-ray spectroscopy mainly focusing on firm spin-parity determinations.Method:High-intensity rare-isotope beams of,,, andbombarded a Be target to induce nucleon removal reactions populating states in.rays were detected by the state-of-the-art-ray tracking array GRETINA. For the direct one-neutron removal reaction, final-state exclusive cross sections and parallel momentum distributions were deduced. Multinucleon removal reactions from different projectiles were exploited to gain complementary information.Results:With the aid of the parallel momentum distributions, an updated level scheme with revised spin-parity assignments was constructed. Spectroscopic factors associated with each state were also deduced.Conclusions:Results were confronted with large-scale shell-model calculations using two different effective interactions, showing excellent agreement with the present level scheme. However, a marked difference in the spectroscopic factors indicates that the full delineation of the transition into the island of inversion remains a challenge for theoretical models.