Exotic resonances of fully-heavy tetraquarks in a lattice-QCD insipired quark model

Fully-heavy tetraquark states, i.e., cc (c) over bar(c) over bar, bb (b) over bar(b) over bar, bb (c) over bar(c) over bar (cc (b) over bar(b) over bar), cb (c) over bar(c) over bar, cb (b) over bar(b) over bar, and cb (c) over bar(b) over bar, are systematically investigated by means of a nonrelativistic quark model based on lattice-QCD studies of the two-body Q (Q) over bar interaction, which exhibits a spin-independent Cornell potential along with a spin-spin term. The four-body problem is solved using the Gaussian expansion method; additionally, the so-called complex scaling technique is employed so that bound, resonance, and scattering states can be treated on the same footing. Moreover, a complete set of four-body configurations, including meson-meson, diquark-antidiquark, and K-type configurations, as well as their couplings, are considered for spin-parity quantum numbers J(P(C)) = 0(+(+)), 1(+(+/-)), and 2(+(+)) in the S-wave channel. Several narrow resonances, with two-meson strong decay widths less than 30 MeV, are found in all of the tetraquark systems studied. Particularly, the fully-charm resonances recently reported by the LHCb Collaboration, at the energy range between 6.2 and 7.2 GeV in the di-J/psi invariant spectrum, can be well identified in our calculation. Focusing on the fully-bottom tetraquark spectrum, resonances with masses between 18.9 and 19.6 GeV are found. For the remaining charm-bottom cases, the masses are obtained within a energy region from 9.8 GeV to 16.4 GeV. All these predicted resonances can be further examined in future experiments.