Hadronic Molecules and $\ddot{I}{‡}_{cJ}(2P)$ Coupled States

Abstract

We investigate hidden-charm exotic mesons based on a coupled-channel framework, where the physical states are described as superpositions of a compact $c\bar{c}$ core (identified with the $\ddot{I}{‡}_{cJ}(2P)$ states) and hadronic components such as $D^{(\ast )}{\bar{D}}^{(\ast )}$. We incorporate meson exchange potentials to describe hadron-hadron interactions and determine model parameters to reproduce the observed masses of $X(3872)$ and $Z(3930)$. The model also predicts a $0^{++}$ bound state consistent with the $X(3860)$. The internal structure is found to be predominantly molecular for the $X(3872)$, while the $X(3860)$ and $Z(3930)$ have larger $c\bar{c}$ components. The coupling between $c\bar{c}$ cores and hadronic components plays a crucial role in generating these states. The resulting wave functions provide insight into the internal structure and decay properties of these exotic states.

6 pages, 1 figure, Proceedings of The 21st International Conference on Hadron Spectroscopy and Structure (HADRON2025), 27th-31st March, 2025