Quark structure of the $$\chi _{\mathrm{c}}(3P)$$ χc(3P) and X(4274) resonances and their strong and radiative decays

We calculate the masses of $$\chi _{\mathrm{c}}(3P)$$ χc(3P) states with threshold corrections in a coupled-channel model. The model was recently applied to the description of the properties of $$\chi _{\mathrm{c}}(2P)$$ χc(2P) and $$\chi _{\mathrm{b}}(3P)$$ χb(3P) multiplets (Ferretti and Santopinto in Phys Lett B 789:550, 2019]. We also compute the open-charm strong decay widths of the $$\chi _{\mathrm{c}}(3P)$$ χc(3P) states and their radiative transitions. According to our predictions, the $$\chi _{\mathrm{c}}(3P)$$ χc(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 $$c {{\bar{c}}}$$ cc¯ $$\chi _…