New theoretical prediction of the ground-state hyperfine splitting in muonium

We have computed a new contribution to the ground-state hyperfine splitting in muonium: -2(α/π)2(m/M)[ln(M/m)]2 E/sub F/ = -6.6 kHz. Uncalculated theoretical contributions are expected to be no larger than a few kHz. The new theoretical estimate, ν/sub theor/ = 4 463 297.9(7.0) kHz is in good agreement with experiment: ν/sub exp/ = 4 463 302.35(0.52) kHz. The bulk of the uncertainty in the theory is due to uncertainty in the measured value of μ/sub μ//μp