“…But in a few-body system, the breaking of symmetry often benefits more to the threshold than to the collective configuration and thus spoils the binding. For instance, in atomic physics, going from Ps 2 to (M + , m + , M − , m − ) makes the system unstable for M/m 2.2 [17,18]. However, when the symmetry is charge-conjugation, the symmetry breaking benefits entirely to the collective state.…”