Development of New Analysis Method for the Precision Measurement of Muoniumu Hyperfine Structure

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K14746
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 15020:Experimental studies related to particle-, nuclear-, cosmic ray and astro-physics
• Research Institution: High Energy Accelerator Research Organization
• Principal Investigator: Shoichiro Nishimura 大学共同利用機関法人高エネルギー加速器研究機構, 物質構造科学研究所, 特別助教 (20836431)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: ミュオン / ミュオニウム / 精密分光 / 超微細構造 / ラビ振動分光

Outline of Final Research Achievements

This research has been conducted to improve the precision of muonium hyperfine structure measurement. First, we have successfully developed Rabi-oscillation spectroscopy, which has a smaller effect of systematic uncertainty than standard spectroscopy. For zero-field measurement, we adapted it to actual experimental data. In high-field experiments, as in the zero-field case, the formulation was also developed, and preparations were completed to achieve high precision.
In addition, a new forward detector was developed to investigate uncertainties due to the stability of the muon beam. The specifications of detector with a fiber scintillator was proceeded, and then, the detector was fabricated. The performance of the detector was evaluated and confirmed to work as expected.

Free Research Field

素粒子物理学

Academic Significance and Societal Importance of the Research Achievements

ここ近年の素粒子物理学において、標準模型を超えた新物理の発見が待ち望まれている。新物理探索の一つの手法として、素粒子の性質を高精度測定して、理論との比較により標準模型の綻びを見つける研究が進められている。電子の仲間である素粒子ミュオンと電子が束縛した状態のミュオニウムは水素原子に類似しており、その超微細構造の精密測定は標準模型の検証と深く関わっている。本研究によってミュオニウム超微細構造の測定精度はさらに向上し、標準模型を超えた新物理探索に貢献している。またその過程で開発したラビ振動分光はミュオニウム以外の短寿命原子分光にも応用が期待される。