True muonium or muononium is an exotic atom made up of an antimuon and a muon. It is yet to be observed, but it may have been generated in the collision of electron and positron beams.
References
True muonium Wikipedia(Text) CC BY-SA
True muonium or muononium is an exotic atom made up of an antimuon and a muon. It is yet to be observed, but it may have been generated in the collision of electron and positron beams.