MUON-ELECTRON CHARGE RATIO ANOMALY $\mathit q_{{{\mathit \mu}^{+}} }/\mathit q_{{{\mathit e}^{-}} }$ $+$ 1

INSPIRE  
VALUE DOCUMENT ID TECN CHG  COMMENT
($1.1$ $\pm2.1$) $ \times 10^{-9}$ 1
MEYER
2000
CNTR + 1s$-$2s muonium interval
1  MEYER 2000 measure the 1s$-$2s muonium interval, and then interpret the result in terms of muon-electron charge ratio $\mathit q_{{{\mathit \mu}^{+}} }/\mathit q_{{{\mathit e}^{-}} }$.
References:
MEYER 2000
PRL 84 1136 Measurement of the 1s-2s Energy Interval in Muonium