Speaker
Description
Muonium is a pure leptonic bound system consisting of a positive muon and an electron, whose energy level structure can be calculated with extremely high precision based on quantum electrodynamics (QED). The MuSEUM experiment aims to measure the ground-state hyperfine structure of muonium by microwave spectroscopy, thereby testing QED and determining the muon magnetic moment and mass with high precision. In 2017, a zero-field measurement at the J-PARC D-Line achieved a relative precision of 160 ppb. More recently, in January–February 2025, our first high-field measurement was conducted at the newly constructed H-Line.
We are now preparing for long-term measurements in the future, aiming to surpass the world’s best precision achieved at LAMPF in 1999. In this presentation, I will report on the development of a stabilized microwave resonance system for long-term operation and on background evaluation through simulations.
