Our present understanding of the structure of the Hoyle state in $$^{12}$$ 12 C and other near-threshold states in $$\alpha $$ α -conjugate nuclei is reviewed in the framework of the $$\alpha $$ α -condensate model. The $$^{12}$$ 12 C Hoyle state, in particular, is a candidate for $$\alpha $$ α -condensation, due to its large radius and $$\alpha $$ α -cluster structure. The predicted features of nuclear $$\alpha $$ α -particle condensates are reviewed along with a discussion of their experimental indicators, with a focus on precision break-up measurements. Two experiments are discussed in detail, firstly concerning the break-up of $$^{12}$$ 12 C and then the decays of heavier nuclei. With more theoretical input, and increasingly complex detector setups, precision break-up measurements can, in principle, provide insight into the structures of states in $$\alpha $$ α -conjugate nuclei. However, the commonly-held belief that the decay of a condensate state will result in N $$\alpha $$ α -particles is challenged. We further conclude that unambiguously characterising excited states built on $$\alpha $$ α -condensates is difficult, despite improvements in detector technology.

中文翻译：

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霍伊尔家族：在轻核中寻找 α-凝聚态

我们目前对 $$^{12}$$ 12 C 中的霍伊尔态结构和 $$\alpha $$ α -共轭核中的其他近阈值状态的理解在 $$\alpha $ $α-凝析模型。特别是 $$^{12}$$ 12 C Hoyle 状态是 $$\alpha $$ α - 凝聚的候选状态，因为它的半径大和 $$\alpha $$ α - 簇结构。回顾了核 $$\alpha $$ α 粒子凝聚物的预测特征，并讨论了它们的实验指标，重点是精确的破裂测量。详细讨论了两个实验，首先是关于 $$^{12}$$ 12 C 的破裂，然后是较重原子核的衰变。随着更多的理论输入和日益复杂的检测器设置，原则上精确的破裂测量可以 深入了解 $$\alpha $$ α 共轭核中的状态结构。然而，人们普遍认为凝聚态的衰变将导致 N $$\alpha $$ α 粒子受到挑战。我们进一步得出结论，尽管检测器技术有所改进，但明确表征基于 $$\alpha $$ α-凝聚物的激发态是困难的。