Fully charm and bottom pentaquarks in a lattice-QCD inspired quark model
Gang Yang, Jialun Ping, Jorge Segovia
Abstract
The fully charm and bottom pentaquarks, i.e., $cccc\overline{c}$ and $bbbb\overline{b}$, with spin-parity quantum numbers ${J}^{P}={\frac{1}{2}}^{\ensuremath{-}}$, ${\frac{3}{2}}^{\ensuremath{-}}$, and ${\frac{5}{2}}^{\ensuremath{-}}$, are investigated within a lattice-QCD inspired quark model, which has already successfully described the recently announced fully charm tetraquark candidate $X(6900)$ and has also predicted several other fully heavy tetraquarks. A powerful computational technique, based on the Gaussian expansion method combined with a complex-scaling range approach, is employed to predict, and distinguish, bound, resonance, and scattering states of the mentioned five-body system. Both baryon-meson and diquark-diquark-antiquark configurations, along with all of their possible color channels are comprehensively considered. Narrow resonances are obtained in each spin-parity channel for the fully charm and bottom systems. Moreover, most of them seem to be compact multiquarks whose wave functions are dominated by either hidden-color baryon-meson or diquark-diquark-antiquark structure or by the coupling between them.