Functional methods for hadron spectroscopy

Abstract

We summarize recent results for four-quark states with hidden and open flavor obtained from a four-quark Bethe-Salpeter/Faddeev-Yakubowsky equation. The approach dynamically predicts the leading internal two-body clusters such as meson-meson, hadroquarkonium or diquark-antidiquark components. For hidden-flavor states, the meson-meson or hadroquarkonium configurations are dominant, while the diquark contributions are small. For open-flavor states, the situation is different and depends on the quark content: The $T_{bb}^{-}$ is a mixture of various components, where the diquark-antidiquark components are dominant, whereas the $T_{cc}^{+}$ is practically entirely dominated by $D{D}^{\ast }$ due to its proximity to the threshold. We also provide details on the analytic continuations and extrapolations to extract states above thresholds.

15 pages, 10 figures, 1 table. Proceedings of the XVIth Quark Confinement and the Hadron Spectrum Conference (QCHSC24), Cairns, Australia, 19-24 August 2024