Veryfication of effects of three-body nuclear force in nuclear structure and reaction processes

2019 Fiscal Year Final Research Report

• Project/Area Number: 16K05353
• 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: Osaka University
• Principal Investigator: Kohno Michio 大阪大学, 核物理研究センター, 協同研究員 (40234710)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: ３体核力 / カイラル有効場理論 / 原子核の飽和性 / 核物質計算 / パウリ排他効果 / 微視的光学模型ポテンシャル / パウリ配置換え効果 / 核媒質中のハイペロン

Outline of Final Research Achievements

The accurate description of nucleon-nucleon (NN) interactions, which is basic for microscopic studies of properties of nuclei, has been advanced by chiral effective field theory. The advantage consists of an ability of systematic introduction of many-nucleon forces. Although the saturation is one of the most fundamental properties of nuclei, the microscopic understanding has been lacking, and its description relies largely on the phenomenology. I have carried out nuclear matter calculations with the chiral NN and 3N interactions, and showed that three-nucleon forces (3NFs) play an essential role in reproducing microscopically saturation properties. On the basis of this observation, I have proceeded to verify the effects of 3NFs in nuclear structures and reactions. The possibility that the Lambda hyperons do not appear in high-density neutron star matter has also been demonstrated by nuclear matter calculations with baryon-baryon interactions in chiral effective field theory.

Free Research Field

原子核理論

Academic Significance and Societal Importance of the Research Achievements

原子核の核子分布密度がほぼ一定であるという飽和性は基盤的性質であるが、これまで微視的な理解はなされていず、現象論的な記述に頼っていた。この研究課題では、３体力が系統的に導入されるカイラル有効場理論の相互作用記述を用いて無限核物質系の計算を行い、３体力の寄与が飽和性を説明することを示した。３体力の寄与は、２体力の構築の段階で消去される自由度の関わる過程が、核媒質中でパウリ原理により受ける影響の重要性を意味する。この理解に立脚して、核構造の面ではスピン軌道力への３体力の望ましい寄与を明らかにし、核反応過程では微視的に構築した光学模型ポテンシャルが、核子と原子核の弾性散乱をよく記述することを示した。