The J/ψ is a meson composed of a charm quark and a charm antiquark. In the S-wave triplet family (where the total quark spin is 1), the J/ψ charmonium is a ground state and the ψ(2S) is a radial excitation of J/ψ. They have the same quantum numbers as a photon: total angular momentum 1, parity -1, and charge conjugation -1.