Present state of the knowledge about charmionium energetical states (i.e. mesons which is built from c quark and c antiquark) and trasitions between these states. Distances between energetic levels according to difference of the masses - for example J/? meson's mass in (1S) state is m=3097 MeV and in (2S) state - m=3686 MeV.
Marking g* means decays with presence of virtual photons, including decays to e+e- and µ+µ-.
Unerctain states and transitions are marked with dashed lines
Source: Particles and fields, Phys. Rev. D., Vol. 66, No 1-I, 2002, p. 719 Table of energy