Hadronic Molecules and $\chi_{cJ}(2P)$ Coupled States

TL;DR

This paper models hidden-charm exotic mesons as superpositions of $c\bar c$ cores and hadronic molecules, using meson exchange potentials to explain observed states like $X(3872)$ and $Z(3930)$.

Contribution

It introduces a coupled-channel framework that combines $c\bar c$ cores with hadronic components, predicting new states and clarifying their internal structures.

Findings

The model reproduces the masses of $X(3872)$ and $Z(3930)$.

It predicts a $0^{++}$ bound state consistent with $X(3860)$.

The $X(3872)$ is predominantly molecular, while others have larger $c\bar c$ components.

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 $\chi_{cJ}(2P)$ states) and hadronic components such as $D^{(*)}\bar D^{(*)}$. 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.