A measurement of proton inelastic scattering of ⁸He at 8.25A MeV at TRIUMF shows a resonance at 3.54(6) MeV with a width of 0.89(11) MeV. The energy of the state is in good agreement with coupled cluster and no-core shell model with continuum calculations, with the latter successfully describing the measured resonance width as well. Its differential cross section analyzed with phenomenological collective excitation form factor and microscopic coupled reaction channels framework consistently reveals a large deformation parameter ${\beta }_2$ = 0.40(3), consistent with no-core shell model predictions of a large neutron deformation. This deformed double-closed shell at the neutron drip-line opens a new paradigm.

在 TRIUMF处以 8.25 A MeV对⁸ He的质子非弹性散射的测量显示共振频率为 3.54(6) MeV，宽度为 0.89(11) MeV。状态能量与具有连续计算的耦合簇和无核壳模型非常吻合，后者也成功地描述了测量的共振宽度。用现象学集体激发形状因子和微观耦合反应通道框架分析其微分横截面一致显示大变形参数${\beta }_2$= 0.40(3)，与大中子变形的无核壳模型预测一致。这种在中子滴线处变形的双封闭壳开辟了一个新的范例。