There are several experimental projects searching for the true muonium. One of them is the μμ-tron experiment (Mumutron) planned at the Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences (INP SB RAS), which has been under development since 2017. The experiment involves the creation of a special low-energy electron–positron collider, which will make it possible to observe the production of true muonium in collisions of electron and positron beams with an intersection angle of 75° with energies of 408 MeV. Thus, the invariant mass of colliding particles will be equal to twice the mass of the muon (m μ =105.658 MeV). To register the exotic atom (in the decay channel into an electron-positron pair), it is planned to create a specialized detector. Apart to the actual detection of true muonium, it is planned to isolate its various states and measure their lifetimes.