Second order in mass ratio radiative-recoil corrections to hyperfine splitting in muonium

Abstract
Radiative-recoil corrections to hyperfine splitting in muonium of order α(Zα)(m/M)2EF and (Z2α)(Zα)(m/M)2EF are calculated. These corrections are of the second order in the small electron-muon mass ratio. An analytic expression [(6ln234)α(Zα)1712(Z2α)(Zα)](m/M)2EF is obtained. Numerically the correction is equal to 0.0351kHz and is of the same order of magnitude as the expected accuracy of the current Los Alamos experiment to measure the hyperfine splitting.