All-heavy tetraquarks with different flavors

In a nonrelativistic potential quark model framework, we carry out a precise calculation of the mass spectrum of the all-heavy tetraquarks with different flavors, $bb\bar{b}\bar{c}$, $cc\bar{c}\bar{b}$, $bb\bar{c}\bar{c}$, and $bc\bar{b}\bar{c}$, by adopting the explicitly correlated Gaussian method. A complete mass spectrum for the $1S$ states is obtained. For the $bb\bar{b}\bar{c}$, $cc\bar{c}\bar{b}$, $bb\bar{c}\bar{c}$, and $bc\bar{b}\bar{c}$ systems, the $1S$ states are predicted to lie in the mass ranges of $\sim(16.06,16.14)$, $\sim(9.65,9.74)$, $\sim(12.89,12.94)$, and $\sim(12.75,12.99)$~GeV, respectively.Moreover, by using the obtained masses and wave functions, we evaluate the fall-apart decay properties within a quark-exchange model.The results show that the $1S$ states of the all-heavy tetraquarks with different flavors may have narrow fall-apart decay widths,which ranging from a few tenths to several MeV. Some all-heavy tetraquarks with different flavors may have good potentials to be established at LHC in their optimal fall-apart decay channels, such as $\Upsilon J/\psi$, $\Upsilon B_c^-$, and $J/\psi B_c^+$.