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 $bc\bar b\bar c, bb\bar c\bar c, cc\bar c\bar b$ and $bb\bar b\bar c$ systems. We employ the Gaussian expansion method to solve the four-body Schr\"odinger equation, and the complex scaling method to identify resonant states. The $bc\bar b\bar c, bb\bar c\bar c, cc\bar c\bar b$ and $bb\bar b\bar c$ 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 $bc\bar b\bar c$ tetraquark states are the most promising ones to be discovered in the near future. We recommend the experimental exploration of the $1^{++}$ and $2^{++}$ $bc\bar b\bar c$ 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.