Fully heavy tetraquark resonant states with different flavors

We use the quark potential model to calculate the mass spectrum of the S-wave fully heavy tetraquark systems with different flavors, including the $bc\overline{b}\overline{c},bb\overline{c}\overline{c},cc\overline{c}\overline{b}$, and $bb\overline{b}\overline{c}$ systems. We employ the Gaussian expansion method to solve the four-body Schrödinger equation, and the complex scaling method to identify resonant states. The $bc\overline{b}\overline{c},bb\overline{c}\overline{c},cc\overline{c}\overline{b}$, and $bb\overline{b}\overline{c}$ resonant states are obtained in the mass regions of (13.2, 13.5), (13.3, 13.6), (10.0, 10.3), (16.5, 16.7) GeV, respectively. Among these states, the $bc\overline{b}\overline{c}$ tetraquark states are the most promising ones to be discovered in the near future. We recommend the experimental exploration of the $1^{++}$ and $2^{++}bc\overline{b}\overline{c}$ states with masses near 13.3 GeV in the $J/\psi \Upsilon$ channel. From the root-mean-square radii, we find that all the resonant states we have identified are compact tetraquark states.