原子核中的类集团气体态

主讲人：Hisashi Horiuchi (掘内旭)

 

时  间：12月9日 15:00

 

地   点：3-317

 

 

    1961-1970年间就读于东京大学，之后在京都大学任讲师、副教授、教授，目前在大阪大学核物理研究中心任协作研究员。曾获日本学术振兴会科学论文奖、仁科纪念奖。其研究领域覆盖核结构和核反应领域：在核结构中，用AMD方法研究平均场、集团态类似的态以及二者的共存；在核反应中主要用共振群和生成坐标方法研究轻核散射以及用AMD方法研究中能区的核子-核子散射。

 

 

    The second 0⁺ state of ¹²C is located near the 3-alpha breakup threshold.  It is called the Hoyle state in honor of astrophysicist Fred Hoyle who predicted the existence of this state which plays a crucial role for the synthesis of ¹²C in the universe.  From the side of the nuclear structure theory, this state is well known as one of the mysterious 0+ states in light nuclei. The understanding of its structure has been actually one of the most difficult and challenging problems of nuclear structure.  Its small excitation energy of 7.66 MeV has been regarded to be difficult to explain by the shell model.  The no-core shell model which is the most advanced modern shell model approach at present has so far not succeeded to reproduce it.  Recently we have proposed to explain this state as a Bose-condensate-like state of 3 alpha clusters. The alpha-cluster condensate-like state is the lowest energy state of the alpha-cluster gas-like state. In nuclear physics, gas-like state of nucleons has been an important subject of study for a long time.  Such a state has a very high excitation energy and therefore has been a subject of nuclear matter and nuclear reaction rather than nuclear structure. On the other hand, the gas-like state of clusters is not a so highly excited state, and can be a discrete state accessible spectroscopically.  We will discuss that in ¹⁶O we have a Bose-condensate-like stateof 4 alpha clusters near the 4-alpha breakup threshold.  Gas-like state of clusters is a new concept of nuclear structure and is now studied in many nuclei both theoretically and experimentally.  As another example we will discuss a state in ¹¹B wich has a gas-like structure of 2-alpha + triton.