Regular Article -Theoretical Physics
Four-quark states with charm quarks in a two-body Bethe–Salpeter approach
Institut für Theoretische Physik, Justus-Liebig Universität Gießen, 35392, Giessen, Germany
2 Helmholtz Forschungsakademie Hessen für FAIR (HFHF), GSI Helmholtzzentrum für Schwerionenforschung, Campus Gießen, 35392, Giessen, Germany
Accepted: 27 March 2022
Published online: 9 April 2022
We study the internal structure of a range of four-quark states with charm quark contributions using a two-body Bethe–Salpeter equation. Thereby, we examine charmonium-like states with hidden charm and quark content , open-charm states with quark content and all-charm states with . In particular we study the internal competition between meson–meson components and diquark–antidiquark components in the wave functions of these states. Our results indicate that the and the are predominantly states and that the recently discovered open-charm state is dominated by an internal component. In both cases the diquark components are negligible. For the all-charm state X(6900) with as yet unknown quantum numbers we identify candidates in the excitation spectra of and states. Furthermore, our framework serves to provide predictions for further, yet undiscovered open and hidden charm four-quark states.
© The Author(s) 2022
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