Study of neutron-eich nuclear structure through the magnetic-moment measurement of excited states of Cu isotopes

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K05390
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Particle/Nuclear/Cosmic ray/Astro physics
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Ichikawa Yuichi 国立研究開発法人理化学研究所, 仁科加速器科学研究センター, 専任研究員 (20532089)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 不安定核 / スピン / 磁気モーメント / RIビーム / 励起状態

Outline of Final Research Achievements

The nuclear structure of neutron-rich Cu isotopes was studied through the magnetic-moment measurement of an excited state of 75Cu. At the experiment carried out at RIKEN RIBF, the RI beam of 75Cu with spin alignment as large as 30% was produced by employing the two-step reaction scheme with momentum-dispersion matching, and its magnetic moment was determined for the first time. As a result of the comparison of the experimental value with theoretical calculations based on the Monte-Carlo shell model, the 75Cu nucleus was found to be regarded as a system of one valence proton orbiting a deformed 74Ni core. Furthermore, this results proposes a picture of nuclear shell evolution in the presence of deformation in the neutron-rich Cu isotopes.

Free Research Field

実験原子核物理

Academic Significance and Societal Importance of the Research Achievements

本研究では、陽子魔法数28近傍の不安定核に対して基底状態のみならず励起状態に対しても磁気モーメントを測定することで、変形の効果を踏まえた上での殻進化の描像を提示した。エキゾチック核の見せる多様性には、殻進化と変形の両者が競合しながら寄与する。本研究は、その統一的な理解への第一歩となるものである。今後、他の魔法数近傍核でも磁気モーメント測定を通じて、詳細な内部構造の検証が可能になると期待される。