Muonium-antimuonium Oscillations in an Extended Minimal Supersymmetric Standard Model

The muonium-antimuonium oscillation process has been studied for decades both experimentally and theoretically. Of particular interest is that such a muonium-antimuonium oscillation is totally forbidden within the Standard Model because the process violates the individual electron and muon number conservation laws by two units. Hence, its observation will be a clear signal of physics beyond the Standard Model. This thesis involves the computation of the muonium-antimuonium oscillation time scale in a variety of Standard Model extensions. First, the gauge independence of the various 1-loop contributions to this process is demonstrated in the Standard Model modified only with the inclusion of right-handed neutrinos which were used to generate light neutrino masses via the see-saw mechanism. Next the muonium-antimuonium oscillation time scale in a supersymmetric (SUSY) extension of the Standard Model is calculated. The lower bound on the ratio of the two Higgs field VEVs is also discussed by using experimental results.