Evaluation of electron-capture and beta-decay rates at stellar environments and nucleosynthesis

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K03855
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 15010:Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics
• Research Institution: Nihon University
• Principal Investigator: SUZUKI Toshio 日本大学, 文理学部, 研究員 (70139070)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 電子捕獲反応 / ベータ崩壊 / 殻模型 / スピン依存型遷移 / 元素合成 / 核Urca過程 / ニュートリノ‐原子核反応 / 中性子ドリップ線・ハロー

Outline of Final Research Achievements

Accurate evaluations of weak rates, that is, electron-capture and beta-decay rates in stellar environments, have been done systematically for Gamow-Teller, first and second forbidden transitions including the nuclear regions where two-major shells such as sd-pf and pf-sdg shells are concerned. These nuclear weak rates thus accumulated have been applied to study nucleosynthesis in stars, cooling and heating of the cores of the stars, and evolution of the stars in their final stages.
Using a new microscopic effective interaction in sd-pf shell, nuclear deformations, or quadrupole components of nuclear forces, are found to play important roles in determining the neutron driplines in fluorine, neon, sodium and magnesium isotopes. Structure of the new two-neutron halo in 29F has been clarified.

Free Research Field

原子核理論

Academic Significance and Societal Importance of the Research Achievements

核領域を拡張し、禁止遷移も含めた天体環境での精密な弱遷移率の新たな評価は、天体での元素合成や星の進化の分野の研究へ応用、反映させることによって、原子核物理、天体物理分野間の共同研究、両分野間の研究のフィードバックをさらに推進させる。また、それぞれの分野での研究も、原子核物理では、二主殻に適用できる有効相互作用の新しい求め方の開発、配位空間の拡張などの点でさらに発展することが期待される。分野の垣根を越えた研究成果は、一般社会での興味と関心を引き、その理解を深めることに貢献する。