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arXiv 2408.07856nucl-thnucl-ex
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从中子数N=50的$^{78}$Ni到$^{70}$Ca的从头算计算

Ab initio computations from $^{78}$Ni towards $^{70}$Ca along neutron number $N=50$

B. S. Hu, Z. H. Sun, G. Hagen, G. R. Jansen, T. Papenbrock

AI总结:

本研究利用手征有效场论的核力开展耦合团簇从头算,探究N=50幻数从$^{78}$Ni到$^{70}$Ca的弱化规律,预测核形变、低能谱等性质,解决了$^{78}$Ni低转动带的从头算模拟难题。

摘要:

我们利用手征有效场论导出的核子-核子力与三核子力,对$^{78}$Ni“南侧”、中子数$N=50$的原子核开展了耦合团簇计算。研究发现,向$^{70}$Ca过渡过程中$N=50$幻数出现弱化,表现为形变的出现以及基态复杂度的提升。对于$^{78}$Ni,我们预测了一条与近期实验数据相符的低转动带,这一问题此前一直是从头算核模型的挑战。$^{76}$Fe、$^{74}$Cr和$^{72}$Ti的基态存在形变,不过球形态与形变态的能量差极小,在不确定性估计范围内无法明确判定基态的形状。在$^{70}$Ca中,四极约束Hartree-Fock计算得到的势能面趋于平缓,形变的刚性减弱。我们还计算了这些丰中子$N=50$核的低能谱与$B({\rm E2})$值。

英文摘要:

We present coupled-cluster computations of nuclei with neutron number $N=50$ "south" of $^{78}$Ni using nucleon-nucleon and three-nucleon forces from chiral effective field theory. We find an erosion of the magic number $N=50$ toward $^{70}$Ca manifesting itself by an onset of deformation and increased complexity in the ground states. For $^{78}$Ni, we predict a low-lying rotational band consistent with recent data, which up until now has been a challenge for ab initio nuclear models. Ground states are deformed in $^{76}$Fe, $^{74}$Cr, and $^{72}$Ti, although the spherical states are too close in energy to unambiguously identify the shape of the ground state within the uncertainty estimates. In $^{70}$Ca, the potential energy landscape from quadrupole-constrained Hartree-Fock computations flattens, and the deformation becomes less rigid. We also compute the low-lying spectra and $B({\rm E2})$ values for these neutron-rich $N=50$ nuclei.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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