Towards the understanding of fully-heavy tetraquark states from various models

We use a color-magnetic interaction model (CMIM), a traditional constituent quark model and a multiquark color flux-tube model to systematically investigate the properties of the states [Q(1)Q(2)] [(Q) over bar (3)(Q) over bar (4)] (Q = c, b). The dynamical investigation indicates that the CMIM can not completely absorb QCD dynamical effects through the effective constituent quark mass and overestimates the color-magnetic interaction in the states under the assumption of the same spatial configurations. The Coulomb interaction plays a critical role in the dynamical model calculations on the heavy hadrons, which induces the fact that none of bound states [Q(1)Q(2)] [(Q) over bar (3)(Q) over bar (4)] can be found in the dynamical models. The color configuration [[Q(1)Q(2)](6c) [(Q) over bar (3)(Q) over bar (4)]((6) over bar)(c)](1) should be taken seriously in the ground states due to the strong Coulomb attraction ] between the [Q(1)Q(2)](6c) and [(Q) over bar (3)(Q) over bar (4)]((6) over barc). The color configuration [Q(1)Q(2)]((3) over barc)[(Q) over bar (2)(Q) over bar (4)](3c)](1), is absolutely dominant in the excited states because of the strong Coulomb attraction within the [Q(1)Q(2)]((3) over barc) and [(Q) over bar (2)(Q) over bar (4)](3c). The J/Psi-pair resonances recently observed by LHCb are difficult to be accommodated in the CMIM. The broad structure ranging from 6.2 to 6.8 GeV can be described as the ground tetraquark state [cc][(c) over bar(c) over bar] in the various dynamical models. The narrow structure X(6900) can be identified as the excited state [cc] [(c) over bar(c) over bar] with L = 1 (L = 2) in the constituent quark model (color flux-tube model).

Automated summary

The study reveals that the color-magnetic interaction model cannot fully absorb QCD dynamical effects, and the Coulomb interaction plays a critical role in dynamical model calculations for heavy quarks. Different color configurations dominate in the ground and excited states of the states investigated.