Search for a novel diatomic molecule consisting of a hydrogen atom and an excited muonic hydrogen atom

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K13980
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 13020:Semiconductors, optical properties of condensed matter and atomic physics-related
• Research Institution: Tohoku University
• Principal Investigator: Yamashita Takuma 東北大学, 高度教養教育・学生支援機構, 助教 (40844965)
• Project Period (FY): 2022-04-01 – 2024-03-31
• Keywords: ミュオン / エキゾチックアトム / 共鳴状態 / オージェ遷移 / X線分光 / 量子少数多体計算

Outline of Final Research Achievements

The muon is an elementary particle with a mass 207 times greater than that of the electron. In this study, the quantum state of a tiny molecule formed when a muon combines two hydrogen nuclei was revealed. In particular, precise calculations were carried out to understand the quantum state of the resonance state (temporary bound state) of the muonic molecule under the electron cloud. By directly obtaining the wavefunction of the four-particle system, it was revealed that the muonic molecule contracts under the electron cloud compared to the isolated muonic molecule, and that the dissociative X-ray emitted by the resonant state of the muonic molecule shows a characteristic energy structure identifying the quantum state. These results, in conjunction with the latest precision X-ray spectroscopy experiments, provide a new picture of the muonic molecules and cascade processes.

Free Research Field

原子物理学

Academic Significance and Societal Importance of the Research Achievements

ミュオン分子は二つの核間距離がミュオンの強力な化学結合によって通常の分子の100分の1程度まで短くなっており、分子内で核融合反応を起こすことが知られています。ミュオン触媒核融合と呼ばれるこの現象は、プラズマを必要としない点で特徴的であり、その効率向上にはミュオン分子を含めたダイナミクスの理解が必要になります。本研究で明らかにしたミュオン分子の共鳴状態は、重水素・三重水素混合標的でのミュオン触媒核融合の効率を大きく左右する状態であり、その検出方法や量子的性質が明らかになったことで、今後より精密な設計が可能になると期待されます。