原子核の深い構造を「のぞき窓」から観察する新手法を実証―パイ中間子やニュートリノの謎に迫る研究への応用に期待―

2026-07-09 京都大学

パリティ移行核反応のイメージ（バトンは「パリティの変化」を表す）©️堂園昌伯 ChatGPT

＜関連情報＞

• https://www.kyoto-u.ac.jp/ja/research-news/2026-07-09-1
• https://academic.oup.com/ptep/advance-article/doi/10.1093/ptep/ptag121/8722632

核内アイソベクトル型0⁻状態の選択的プローブとしてのパリティ移行(16O,16F(0⁻,g.s.))反応 Parity-transfer (16O, 16F(0−, g.s.)) reaction as a selective probe of isovector 0− states in nuclei

M Dozono,M Ichimura,S Michimasa,M Takaki,M Kobayashi,M Matsushita,S Ota,H Tokieda,N Fukuda,N Inabe,…
Progress of Theoretical and Experimental Physics  Published:30 June 2026
DOI:https://doi.org/10.1093/ptep/ptag121

Abstract

We demonstrate that the parity-transfer (¹⁶O, ¹⁶F(0⁻, g.s.)) reaction provides a selective probe of isovector 0⁻ excitations in nuclei. This reaction selectively populates unnatural-parity states through a 0⁺ → 0⁻ transition in the projectile. The excitation-energy spectrum of ¹²B was reconstructed via the ¹²C(¹⁶O, ¹⁶F(0⁻, g.s.)) reaction at 247 MeV/u from the coincident detection of the ¹⁵O + p decay products of ¹⁶F. The known 0⁻ state at E_x = 9.3MeV was clearly observed with an enhanced forward cross section, confirming the selectivity of the reaction. The structures observed at E_x = 6.6 ± 0.4 and 14.8 ± 0.3MeV exhibit forward-peaked angular distributions and are suggested to contain significant 0⁻ strength. These results demonstrate that the parity-transfer reaction provides a powerful probe of 0⁻ excitations and highlight its potential for systematic studies of spin-isospin modes, including pion-related dynamics, in nuclei.