Quark structure of the χ _c(3P) and X (4274) resonances and their strong and radiative decays

We calculate the masses of χ _c(3P) states with threshold corrections in a coupled-channel model. The model was recently applied to the description of the properties of χ _c(2P) and χ _b(3P) multiplets (Ferretti and Santopinto in Phys Lett B 789:550, 2019]. We also compute the open-charm strong decay widths of the χ _c(3P) states and their radiative transitions. According to our predictions, the χ _c(3P) states should be dominated by the charmonium core, but they may also show small meson-meson components. The X (4274) is interpreted as a c c̅ χ _c1(3P) state. More information on the other members of the χ _c(3P) multiplet, as well as a more rigorous analysis of the X (4274)’s decay modes, are needed to provide further indications on the quark structure of the previous resonance.