Possible triply heavy tetraquark states in a chiral quark model

In the present work, the triply heavy tetraquarks states QQ Q over bar q over bar with Q = (c; b) and q = (u; d; s) with all possible quantum numbers are systematically investigated in the framework of the chiral quark model with the resonating ground method. Two kinds of structures, including the meson-meson configuration (the color-singlet channels and the hidden-color channels) and the diquark-antidiquark configuration (the color sextet-antisextet and the color triplet-antitriplet), are considered. In the considered system, several bound states are obtained for the ccc over bar q', bbc over bar q', and bcc over bar q over bar tetraquarks. From the present estimations, we find that the coupled-channel effect is of great significance for forming below-threshold tetraquark states, which are stable for strong decays.