Pseudoscalar pole terms contributions to hadronic light-by-light   corrections to the muonium hyperfine splitting
  The contribution of pseudoscalar pole diagrams to the hadronic light-by-light corrections of order alpha^3 E_F to the ground state hyperfine splitting in hydrogenic atom is calculated in the pseudoscalar pole terms approximation. The vector dominance model for the form factor of the transition of a pseudoscalar meson into two photons is used. With the account of new experimental data on the cross sections sigma (e^+e^-\to \rho, \omega \to \pi^0(\eta)\gamma) in the SND and CMD-2 experiments some other hadronic corrections to the muonium hyperfine splitting are calculated. 
R.N.Faustov (Scientific Council for Cybernetics RAS), A.P.Martynenko   (Samara State University)