Feasibility study of true muonium discovery with the CERN-SPS H4 positron beam

True muonium ( μ + μ − ) is one of the heaviest and smallest electromagnetic bound states not containing hadrons, and has never been observed so far. In this work we show 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 − → TM interaction on resonance ( s ∼ 2 m μ ).