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

Abstract

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∼2mμ). Published by the American Physical Society 2024