中文摘要：

α团簇在轻α共轭核基态及激发态中广泛存在,轻核的α团簇结构不仅对核天体物理中核合成过程和元素丰度具有决定性影响,而且这些态的精确数据还成为检验各种新型多体理论和核力的天然实验室.本文简要总结了描述α团簇的不同理论方法,尤其比较了这些不同方法对12C Hoyle态的最新研究结果,各种理论都支持Hoyle态是一个具有较大尺寸的团簇结构,但对α团簇在Hoyle态中的存在形式——比如α凝聚,α气体或是α晶体结构,目前还没有达成共识;进一步从实验角度介绍了α团簇衰变的高精度符合测量及转动态的集体激发.对α团簇结构尤其12C Hoyle态及16O类Hoyle态中α存在形式的确认需要深入理解这些团簇态的集体激发行为,任何实质性进展不仅高度依赖高精度实验数据,而且需要新的多体理论解释,而这其中需要合理考虑核子-核子、团簇-团簇关联及连续谱的影响.

英文摘要：

The degree of freedom of α cluster exists widely in light α conjugate nuclei, which not only plays essential roles in the synthesis of elements and abandance of elements in nuclear astrophysics but also serves as the natural laboratory to test various new many-body theories and nuclear force due to the available high precision data. This article briefly summarizes the different theoretical approaches for alpha-cluster and compares the results of 12 C Hoyle state with these approaches. All the theories support the structure of Hoyle state with a more extended size compared with ground state. However, a consensus has not be reached about how α clusters stay inside Hoyle state, where several candidate states are possible, such as α condensate state, α gas or crystalline arrangements of the α-particles. Further more, we also introduce the new experimental measurements of α decay and collective excitation of rotational band. In order to pin down the existence form of α in Hoyle state, a deeper knowledge of the collective excitation of cluster is needed. The essential progress can only be possible by high combination of new data with high precision and new many-body theory, where the roles of nucleon-nucleon correlation, cluster-cluster correlation and continuum are needed to be included reasonably.