Canonical description of the new LHCb resonances

The LHCb Collaboration has recently observed four J/ψϕ structures called X(4140), X(4274), X(4500), and X(4700) in the B+→J/ψϕK+ decays. We study them herein using a nonrelativistic constituent quark model in which the degrees of freedom are quark-antiquark and meson-meson components. The X(4140) resonance appears as a cusp in the J/ψϕ channel due to the near coincidence of the Ds±Ds*± and J/ψϕ mass thresholds. The remaining three [X(4274), X(4500), and X(4700)] appear as conventional charmonium states with quantum numbers 3P31, 4P30, and 5P30, respectively, and their masses and widths are slightly modified due to their coupling with the corresponding closest meson-meson thresholds. A particular feature of our quark model is a lattice-based screened linear confining interaction that has been constrained in the light-quark sector and usually produces higher excited heavy-quark states with lower masses than standard quark model predictions.