Production of bound {$\mu^{+}\mu^{-}$}-systems in relativistic heavy ion   collisions
  Dimuonium (the bound system of two muons, $\mu^+\mu^-$-atom) has not been observed yet. In this paper we discuss the electromagnetic production of dimuonium at RHIC and LHC in relativistic heavy ion collisions. The production of parastates is analyzed in the equivalent photon approximation. For the treatment of orthostates, we develop a three photon formalism. We determine the production rates at RHIC and LHC with an accuracy of a few percent and discuss problems related to the observation of dimuonium. 
I. F. Ginzburg, U. D. Jentschura, S. G. Karshenboim, F. Krauss, V. G.   Serbo, G. Soff