Determine the nature of the fully charmed tetraquark 1+ state

Determine whether the predicted fully charmed tetraquark $cc\bar{c}\bar{c}$ state with $J^P=1^+$ and mass $6071.1(14)$ MeV is a bound state or a resonance, and investigate it through the $\eta_c e^+e^-$ channel.

Background

The lattice quark potential model predicts a JP=1+J^P=1^+ fully charmed tetraquark at $6071.1(14)$ MeV, only $10.9(14)$ MeV below the calculated ηcJ/ψ\eta_c J/\psi threshold. Because this binding is small, the interpretation is sensitive to the chosen potential and is less reliable than the deeply bound JP=0+J^P=0^+ state. The authors therefore leave unresolved whether the state is genuinely bound or instead a resonance, while identifying the ηce+e−\eta_c e^+e^- channel as a possible means of investigating it.

References

The $JP=1+$ state at $6071.1(14)$ MeV lies only $10.9(14)$ MeV below the $\eta_c J/\psi$ threshold. Since the binding energy is so small, this assignment may depend on the choice of potential, and its existence as a bound state is therefore less firm. Whether the state is a bound state or a resonance, it can be investigated in the $\eta_c e+e-$ channel.

— Fully charmed tetraquarks on the Lattice with controlled errors  (2610.07818 - Zhang et al., 6 Oct 2026) in Results section, discussion following Table 1