Feasibility study of True Muonium discovery with CERN-SPS H4 positron beam

Abstract

True muonium (${\mu }^{+}{\mu }^{-}$) is one of the heaviest and smallest electromagnetic bound states not containing hadrons, and has never been observed so far. In this work it is shown that the spin-1 TM state (ortho-TM) can be observed at a discovery level of significance in three months at the CERN SPS North-Area H4A beam line, using 43.7 GeV secondary positrons. In this way, by impinging the positrons on multiple thin low-Z targets, ortho-TM, which decays predominantly to $e^{+}{e}^{-}$, can be produced from $e^{+}{e}^{-}\to TM$ interactions on resonance ($\sqrt{s}\sim 2m_{\mu }$).