Scientists have discovered for the first time the existence of molecular structures in the ground state of atomic nuclei
2023-11-27
Reporters learned from the Institute of Modern Physics of the Chinese Academy of Sciences on November 25 that its researchers and collaborators recently confirmed the existence of molecular structure in the ground state of the atomic nucleus through experiments for the first time. The study was published in the international physics journal Physical Review Letters and was reported online as a highlight work by the American Physical Society's Physics journal. An atomic nucleus is a quantum multibody system composed of nucleons such as protons and neutrons. The interactions between nucleons form various interesting atomic nucleus structures, ranging from spherical nuclei to deformed nuclei, and even sparse surface density neutron halo nuclei. The appearance of cluster structures within atomic nuclei is a particularly interesting phenomenon among these structures. The cluster structure in the ground state of atomic nuclei is not common. The discussion about the structure of ground state clusters can be traced back to 1938, when theoretical physicists analyzed α The binding energy of conjugated nuclei suggests that there may exist in the ground states of atomic nuclei such as beryllium-8, carbon-12, and oxygen-16 α The molecular group structure. But this theoretical hypothesis has never been confirmed. Recently, researchers and collaborators of the Institute of Modern Physics of the Chinese Academy of Sciences confirmed for the first time the existence of a molecular structure in the ground state of neutron rich nuclear beryllium-10 with novel experimental methods. The experiment was conducted at the Radioactive Beam Factory (RIBF) of the Japanese Institute of Physical and Chemical Research. The research team investigated the knock out response of beryllium-10 through inverse kinematics α Group structure. In the experiment, a secondary beam of 0.5 times the speed of light from beryllium-10 bombarded a 2mm thick solid hydrogen target, binding it to the beryllium-10 core α The group is knocked out by protons and hardly transfers any momentum to the residual nucleus, maintaining the group structure information in the beryllium-10 ground state. The experimental results indicate that the experimental cross-section of the knockout reaction is very consistent with the theoretical predictions under the microscopic model, thus verifying the long-standing hypothesis of the molecular structure of the beryllium-10 ground state, namely the formation of α-α Dumbbell shaped core, with two valence neutrons rotating vertically around the core axis. Similar structures can be found at the atomic scale, but they are very rare in the nuclear ground state. This study provides experimental evidence for the theoretical description of the molecular structure of nuclear ground states for the first time, and further explores the molecular structure of neutron rich nuclear ground states α The evolution of group structure has opened up directions. (Lai Xin She)
Edit:Hu Sen Ming Responsible editor:Li Xi
Source:people.com.cn
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