STATUS AND PROSPECTS OF THE MUONIUM EXPERIMENT AT J-PARC

A microwave spectroscopy experiment of muonium atoms are being prepared at J-PARC in Japan, aiming at an improved relative precision at a level of 10-8 in determination of the muonic magnetic moment. A major improvement of statistical uncertainty is due to higher muon intensity of the pulsed beam at J-PARC, while further improvements are expected for systematic uncertainties. Reduction of sources of systematic uncertainties are being studied: those arising from microwave power fluctuations, magnetic field inhomogeneity, muon stopping distribution and gas-density shift of resonance frequencies. Status and prospects of studies and developments of the experiment is presented in this paper.