ηc- and J/ψ-isoscalar meson bound states in the hadro-charmonium picture

We study ηc- and J/ψ-isoscalar meson bound states in the hadro-charmonium picture. In the hadro-charmonium, the four qq¯cc¯ quarks are arranged in terms of a compact charm-anticharm pair, cc¯, embedded in light hadronic matter, qq¯, with q=u, d or s. The interaction between the charmonium core and the light matter can be written in terms of the multipole expansion in QCD, with the leading term being the E1 interaction with chromo-electric field Ea. The spectrum of ηc- and J/ψ-isoscalar meson bound states is calculated and the results compared with the existing experimental data. Keywords: Hadro-charmonium, QCD multipole expansion, XYZ exotics, Tetraquark