Scalar mesons in a linear sigma model with (axial-)vector mesons

TL;DR

This paper investigates the nature of scalar mesons using an extended Linear Sigma Model with various mesons, concluding that scalar states above 1 GeV are likely quark-antiquark pairs.

Contribution

It introduces an extended Linear Sigma Model including multiple meson types and performs global fits to determine the quark content of scalar mesons.

Findings

Scalar states above 1 GeV are preferred as quark-antiquark states.

The model successfully fits meson masses and decay properties.

Results support the quark-antiquark structure of higher-mass scalar mesons.

Abstract

The structure of the scalar mesons has been a subject of debate for many decades. In this work we look for $\bar{q}q$ states among the physical resonances using an extended Linear Sigma Model that contains scalar, pseudoscalar, vector, and axial-vector mesons both in the non-strange and strange sectors. We perform global fits of meson masses, decay widths and amplitudes in order to ascertain whether the scalar $\bar{q}q$ states are below or above 1 GeV. We find the scalar states above 1 GeV to be preferred as $\bar{q}q$ states.