标题： 精确的质量测量在锆区确定了中子中壳层处的质质量面$N=66$ 显示英文标题

标题： Precision mass measurements in the zirconium region pin down the mass surface across the neutron midshell at $N=66$

摘要： 精确的质量测量对 $^{104}$Y, $^{106}$Zr, $^{104,104m,109}$Nb 和 $^{111,112}$Mo 进行，使用的是在在线离子引导同位素分离器设施中的 JYFLTRAP 双彭宁阱质量光谱仪。 在 $^{104}$Nb 中长寿命态的顺序被明确确立。 在$N=66$中子中壳层附近的两中子分离能趋势似乎比原子质量评估2020年对$_{39}$Y 和$_{40}$Zr 同位素链的外推更陡峭，而对于$_{41}$Nb 链则更平缓，这表明在$Z=40$附近可能存在一个间隙。 实验结果与使用振动和旋转修正进行的BSkG2模型计算进行了比较。 它们都预测了$^{106}$Zr 的两个低能极小值。 虽然未修改的BSkG2模型无法预测两中子分离能的趋势，但选择计算中更形变的极小值并去除振动修正后，计算结果更符合实验数据。 对于Zr同位素中的$2^+_1$激发能和电荷半径差异也是如此。 这些结果强调了在大规模模型中改进集体修正处理的重要性，以及进一步发展超越平均场技术的必要性。 显示英文摘要

摘要： Precision mass measurements of $^{104}$Y, $^{106}$Zr, $^{104,104m,109}$Nb, and $^{111,112}$Mo have been performed with the JYFLTRAP double Penning trap mass spectrometer at the Ion Guide Isotope Separator On-Line facility. The order of the long-lived states in $^{104}$Nb was unambiguously established. The trend in two-neutron separation energies around the $N=66$ neutron midshell appeared to be steeper with respect to the Atomic Mass Evaluation 2020 extrapolations for the $_{39}$Y and $_{40}$Zr isotopic chains and less steep for the $_{41}$Nb chain, indicating a possible gap opening around $Z=40$. The experimental results were compared to the BSkG2 model calculations performed with and without vibrational and rotational corrections. All of them predict two low-lying minima for $^{106}$Zr. While the unaltered BSkG2 model fails to predict the trend in two-neutron separation energies, selecting the more deformed minima in calculations and removing the vibrational correction, the calculations are more in line with experimental data. The same is also true for the $2^+_1$ excitation energies and differences in charge radii in the Zr isotopes. The results stress the importance of improved treatment of collective corrections in large-scale models and further development of beyond-mean-field techniques.