Probing the substructure of $f_0(1370)$

TL;DR

This study investigates the internal structure of the scalar meson $f_0(1370)$ using an effective nonlinear chiral Lagrangian, revealing it is mainly a quark-antiquark state with some four-quark and glue components.

Contribution

The paper introduces a comprehensive analysis of scalar mesons incorporating mixings among quark-antiquarks, four-quarks, and glue components, using Monte Carlo simulations to identify the dominant structure of $f_0(1370)$.

Findings

$f_0(1370)$ is predominantly a quark-antiquark state.

The meson has a substantial $s{ar s}$ component.

Small remnants of four-quark and glue components are present.

Abstract

Within an effective nonlinear chiral Lagrangian framework the substructure of $f_0(1370)$ is studied. The investigation is conducted in the context of a global picture of scalar mesons in which the importance of the underlying connections among scalar mesons below and above 1 GeV is recognized and implemented. These connections are due to the mixings among various quark-antiquarks, four-quarks and glue components and play a central role in understanding the properties of scalar mesons. Iterative Monte Carlo simulations are first performed on the 14-dimensional parameter space of the model and sets of points in this parameter space (the global sets) that give an overall agreement with all experimental data on mass spectrum, various decay widths and decay ratios of all isosinglet scalar states below 2 GeV are determined. Then within each global set, subsets that give closest agreement for the properties of $f_0(1370)$ are studied. Unlike the properties of other isosinglet states that show a range of variation within each global set, it is found that there is a clear signal for $f_0(1370)$ to be predominantly a quark-antiquark state with a substantial $s {\bar s}$ component, together with small remnants of four-quark and glue components.