9C破裂产物核芯径向动量测量

With the development of Radioactive Nuclear Beam(RNB) facility, halo structure are discovered in nuclei. For challenging the traditional nuclear theory based on stable nuclei, the halo is the frontier of nuclear physics. All the confirmed two-nucleon halo nuclei are Borromean nuclei, which any two body in the nuclei are unbounded. Whether the non-Borromean nuclei are exist is a interesting question. The 9C is a weakly bound candidate, it consists of the halo 8B and a proton, the S(p) is 1.3MeV, the S(2p) is 1.43MeV. It is not clear whether the configuration of 9C is 8B+p or 7Be+2p? so It’s worth to investigate the structure of 9C. Experimentally identification of the halo nuclei consist of two features: if the enhanced cross sections are observed, it will be named as halo candidate, when the narrow longitudinal momentum distributions of the core are observed, it’s a confirmed halo nuclei. Previous experiments of cross sections measurement of 9C are partly support the halo structure. But there is no data of the longitudinal momentum distributions measurement, so it is the aim of this project. We pretend to measure the longitudinal momentum distributions of 8B and 7Be from the 9C breakup reaction. If the experimental result supports the 7Be+2p configuration, it will be the first non-Borromean two-nucleon halo nuclei.

原子核晕结构是近年来伴随着放射性束装置的发展而发现的新核结构，是核物理研究的前沿和热点。目前实验上确认的双核子晕核如 6He,11Li,14Be,17B, 17Ne都是Borromean核，即构成晕核的三体中任意两体非束缚。那么是否存在non-Borromean结构的晕核？9C是一个可能的候选核，它由一个确定的晕核8B加一个质子构成，其单、双质子分离能分别为1.3MeV和1.43MeV，是弱束缚核。9C究竟是8B+p还是7Be+2p结构，目前并不清楚。实验上确定一个核是否是晕核主要有2个判据，增大的相互作用截面和核芯径向动量窄分布。此前对9C截面的测量中部分支持晕结构。而关于其核芯径向动量分布则没有实验数据。本基金希望通过破裂反应测量8B和7Be碎片的径向动量分布来研究9C结构。如果试验结果支持9C是7Be+2p构成的晕核，它将是实验上首次发现的non-Borromean结构的双核子晕核。