We use QCD Laplace sum-rules to study meson-hybrid mixing in vector (1 −− ) heavy quarkonium. We compute the QCD cross-correlator between a heavy meson current and a heavy hybrid current within the operator product expansion. In addition to leading-order perturbation theory, we include four-and sixdimensional gluon condensate contributions as well as a six-dimensional quark condensate contribution. We construct several single and multi-resonance models that take known hadron masses as inputs. We investigate which resonances couple to both currents and so exhibit meson-hybrid mixing. Compared to single resonance models that include only the ground state, we find that models that also include excited states lead to significantly improved agreement between QCD and experiment. In the charmonium sector, we find that meson-hybrid mixing is consistent with a two-resonance model consisting of the J/ψ and a 4.3 GeV resonance. In the bottomonium sector, we find evidence for meson-hybrid mixing in the Υ(1S), Υ(2S), Υ(3S), and Υ(4S).

We explore conventional meson-hybrid mixing in J PC ¼ 1 þþ heavy quarkonium using QCD Laplace sum rules. We calculate the cross-correlator between a heavy conventional meson current and heavy hybrid current within the operator product expansion, including terms proportional to the four-and sixdimensional gluon condensates and the six-dimensional quark condensate. Using experimentally determined hadron masses, we construct models of the 1 þþ charmonium and bottomonium mass spectra. These models are used to investigate which resonances couple to both currents and thus exhibit conventional meson-hybrid mixing. In the charmonium sector, we find almost no conventional mesonhybrid mixing in the χ c1 ð1PÞ, minimal mixing in the Xð3872Þ, and significant mixing in both the Xð4140Þ and Xð4274Þ. In the bottomonium sector, we find minimal conventional meson-hybrid mixing in the χ b1 ð1PÞ and significant mixing in both the χ b1 ð2PÞ and χ b1 ð3PÞ.

Constituent mass predictions for axial vector (i.e., J P = 1 + ) cc and bb colour-antitriplet diquarks are generated using QCD Laplace sum rules. We calculate the diquark correlator within the operator product expansion to NLO, including terms proportional to the four-and six-dimensional gluon and six-dimensional quark condensates. The sum-rules analyses stabilize, and we find that the mass of the cc diquark is 3.51 GeV and the mass of the bb diquark is 8.67 GeV. Using these diquark masses as inputs, we calculate several tetraquark masses within the Type-II diquark-antidiquark tetraquark model.

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We use QCD Laplace sum-rules to explore mixing between conventional mesons and hybrids in the heavy quarkonium vector J PC = 1 −− channel. Our cross-correlator includes perturbation theory and contributions proportional to the four-dimensional and six-dimensional gluon condensates. We input experimentally determined charmonium and bottomonium hadron masses into both single and multi-resonance models in order to test them for conventional meson and hybrid components. In the charmonium sector we find evidence for meson-hybrid mixing in the J/ψ and a ≈ 4.3 GeV resonance. In the bottomonium sector, we find that the Υ(1S ), Υ(2S ), Υ(3S ), and Υ(4S ) all exhibit mixing.