AWhat changed
Meyer and colleagues measured the muonium 1s–2s interval using counterpropagating two-photon laser excitation, photoionization and muon detection. Pulse-by-pulse laser diagnostics, an iodine frequency reference and deuterium control measurements supported the analysis of 99 muonium events. After correcting to the hyperfine centroid, they reported a transition frequency of 2,455,528,941.0±9.8 MHz. Comparisons with bound-state quantum electrodynamics provided conditional determinations of the positive-muon mass and constraints on the muon–electron charge ratio.
Scientific scope
Meyer and colleagues measured the muonium 1s–2s interval using counterpropagating two-photon laser excitation, photoionization and muon detection. Pulse-by-pulse laser diagnostics, an iodine frequency reference and deuterium control measurements supported the analysis of 99 muonium events. After correcting to the hyperfine centroid, they reported a transition frequency of 2,455,528,941.0±9.8 MHz. Comparisons with bound-state quantum electrodynamics provided conditional determinations of the positive-muon mass and constraints on the muon–electron charge ratio. The measured line centre depends on pulse-dependent lineshape modelling, reference calibration and Doppler and hyperfine corrections. Mass-ratio extraction uses QED and equal-magnitude charges; interpreting the same spectrum as a charge-ratio constraint instead uses external mass information. These are distinct conditional interpretations, not independent simultaneous measurements of both unknown ratios. The historical result and its uncertainty do not establish exact charge equality, exclude every new interaction or replace later theoretical updates.
Evidence
The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. The measured line centre depends on pulse-dependent lineshape modelling, reference calibration and Doppler and hyperfine corrections. Mass-ratio extraction uses QED and equal-magnitude charges; interpreting the same spectrum as a charge-ratio constraint instead uses external mass information. These are distinct conditional interpretations, not independent simultaneous measurements of both unknown ratios. The historical result and its uncertainty do not establish exact charge equality, exclude every new interaction or replace later theoretical updates.
Contributors
- The named authors in the research record · SCIENCE: These are the listed authors of the cited contribution sources. Paper authorship does not quantify individual effort. An incomplete list is explicitly marked; same names are not automatically merged.
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