The first prediction of muon-containing trilepton and tetralepton bound and resonant states -- few-body systems of charged leptons bound purely by the QED Coulomb interaction, generalizing dipositronium (Ps2). The three- and four-body Schrodinger equation is solved with the Gaussian expansion method and resonances are extracted using the complex scaling method, yielding a spectrum of states (binding energies of order 1-30 eV, widths below about 0.07 eV) together with their spin configurations and root-mean-square radii. By treating these systems as the QED counterparts of fully-heavy tetraquarks, it shows how the extra color degree of freedom in QCD reshapes which bound and resonant states can exist.
This particle-physics paper presents the first prediction of muon-containing tetralepton bound and resonant states, extending beyond the simplest tetralepton system, dipositronium (Ps2). Working in a…