Dynamical study of the light scalar mesons below 1 GeV in a flux-tube model

TL;DR

This study models light scalar mesons below 1 GeV as tetraquark states using a flux-tube approach with multi-body confinement, successfully explaining some mesons' properties but not all.

Contribution

It introduces a flux-tube model with multi-body confinement to describe light scalar mesons as tetraquarks, providing new insights into their structure.

Findings

$\sigma$, $\kappa$ fit well as tetraquarks in the model.

The first radial excited state of $[ud][ar{u}ar{d}]$ is near 1019 MeV.

$a_0(980)$ cannot be explained as a tetraquark in this framework.

Abstract

The light scalar mesons below 1 GeV as tetraquark states are studied in the framework of the flux-tube model, the multi-body confinement instead of the additive two-body confinement is used. From the calculated results, we find that the light scalar mesons, $\sigma$, $\kappa$ could be well accommodated in the diquark-antidiquark tetraquark picture in the flux-tube model and they could be color confinement resonances. The mass of the first radial excited state of $[ud][\bar{u}\bar{d}]$ is 1019 MeV, which is close to the mass of $f_0(980)$. Whereas $a_0(980)$ can not be fitted in this interpretation.