P-wave $c\bar{c}$ meson contributions in exotic hadrons

TL;DR

This paper investigates the internal structure of exotic hadrons like X(3872) using a coupled-channel model that includes both $c\bar{c}$ states and molecular components, supporting a mixed nature.

Contribution

It introduces a systematic coupled-channel approach to analyze the composition of exotic hadrons, fixing parameters to experimental masses and predicting structures.

Findings

X(3872) is dominated by molecular components.

X(3860) and Z(3930) have significant $c\bar{c}$ contributions.

The model supports a mixed state interpretation of these exotic hadrons.

Abstract

The nature of the $X(3872)$ and other exotic hadrons has been a subject of extensive investigation. While various theoretical models have been proposed, experimental evidence suggests that the $X(3872)$ may be a mixture state of a hadronic molecule and a $c\bar{c}$ core. In this work, we perform a systematic study of hidden-charm tetraquark candidates $X(3860)$, $X(3872)$, and $Z(3930)$ using a coupled-channel model that incorporates both $c\bar{c}$ states and $D^{(*)}\bar{D}^{(*)}$ hadronic molecular components. The model parameters are fixed to reproduce the masses of the $X(3872)$ and $Z(3930)$, and the resulting framework is used to predict the mass and structure of the $0^{++}$ state associated with the $X(3860)$. Our results support the mixture interpretation of these exotic hadrons, exhibiting strong attractions from the transition potential between $c\bar{c}$ and $D^{(*)}\bar{D}^{(*)}$ components. The molecular component dominates in the $X(3872)$, while the $c\bar{c}$ component plays a more prominent role in the $X(3860)$ and $Z(3930)$.