Exploring doubly heavy tetraquarks in a constituent-quark-model based meson-meson coupled-channels approach

The LHCb Collaboration announced in 2021 the discovery of a new tetraquarklike state, named (+), with minimum quark content , close to the (0*+) threshold. This has motivated countless theoretical works trying to identify the dynamics which is responsible of the formation of such state; in particular, the one performed by us in Ortega et al. [Phys. Lett. B 841, 137918 (2023); Phys. Lett. B847, 138308(E) (2023)], where a (0*+) molecular candidate whose mass, width, scattering length, and effective ranges are in reasonable agreement with experimental measurements. We explore herein the possibility of having (+) partners in all doubly heavy tetraquark sectors, considering doubly represented light antiquarks , , or , and taking into account all possible spin-parity quantum numbers. The computation is done using a constituent-quark-model based meson-meson coupled-channels framework which has been tested many times in the last fifteen years describing conventional heavy mesons and baryons, their coupling with hadron-hadron thresholds but also in exploring its application to compact multiquark structures. The advantage of using an approach with such a relatively large history is that it allows us to make predictions because all the parameters have already been constrained from our previous works. Then, from this perspective, we present a parameter-free model-dependent prediction of doubly-heavy tetraquarks that may be partners of the discovered (+) state.