Fully-heavy tetraquarks: bb(c)over-bar (c)over-bar and bc(b)over-bar (c)over-bar

In the framework of a nonrelativistic chiral quark model, we continue to study the mass spectra of the fully-heavy bb (c) over bar (c) over bar and bc (b) over bar (c) over bar tetraquarks. In the present calculations, two structures, meson-meson [(Q) over bar Q] [(Q) over bar Q] and diquark-antidiquark [QQ] [(Q) over bar (Q) over bar] (Q = c or b), and their mixing, along with all possible color, spin configurations are considered. The calculations suggest that no bound state can be formed for bb (c) over bar (c) over bar and bc (b) over bar (c) over bar systems. However, resonances are possible because of the color structure. Several resonances are predicted and their stabilities are checked using the real scaling method.