Coupled-channel analysis of the X(3872)

TL;DR

This paper analyzes the X(3872) as an axial-vector charmonium state within a multichannel quark-meson model, successfully describing certain experimental features but not the resonance pole, indicating the need for further refinement.

Contribution

It applies a coupled-channel multichannel framework to study the X(3872), highlighting the model's ability to reproduce experimental data without identifying a dynamical resonance pole.

Findings

Successfully describes the X(3872) structure near the threshold.

Fails to find a dynamical resonance pole for X(3872).

Highlights limitations and potential improvements of the model.

Abstract

The X(3872) is studied as an axial-vector charmonium state in the multichannel framework of the Resonance-Spectrum-Expansion quark-meson model, previously applied to a variety of other puzzling mesonic resonances. Included are the open-charm pseudoscalar-vector and vector-vector channels, the most important of which is the S-wave $\bar{D}^{*0}D^{0}$ + $D^{*0}\bar{D}^{0}$ channel, which practically coincides with the X(3872) structure. The two free parameters of the model are tuned so as to roughly reproduce the $\chi_{c1}(3511)$ mass as well as the enhancement just above the $\bar{D}^{*0}D^{0}$ / $D^{*0}\bar{D}^{0}$ threshold. The present model is able to describe the shape of the latter data quite well. However, as no dynamical resonance pole is found, the X(3872) and X(3940) cannot be reproduced simultaneously, at this stage. A possible further improvement is discussed.