Scalar isoscalar mesons and the scalar glueball from radiative $J/\psi$ decays

TL;DR

This paper performs a coupled-channel analysis of BESIII data on radiative $J/$ decays to identify and characterize scalar mesons and the scalar glueball, determining their properties and decay modes.

Contribution

It provides a detailed analysis of scalar mesons and the scalar glueball from experimental data, including their masses, widths, and decay patterns, with a focus on the glueball candidate.

Findings

Identified ten isoscalar scalar mesons with specific masses and widths.

Observed octet scalar states mainly in the 1500-2100 MeV range.

Determined the scalar glueball mass to be approximately 1865 MeV with a width of 370 MeV.

Abstract

A coupled-channel analysis of BESIII data on radiative $J/\psi$ decays into $\pi\pi$, $K\bar K$, $\eta\eta$ and $\omega\phi$ has been performed. The partial-wave amplitude is constrained by a large number of further data. The analysis finds ten isoscalar scalar mesons. Their masses, widths and decay modes are determined. The scalar mesons are interpreted as mainly SU(3)-singlet and mainly octet states. Octet isoscalar scalar states are observed with significant yields only in the 1500-2100\,MeV mass region. Singlet scalar mesons are produced over a wide mass range but their yield peaks in the same mass region. The peak is interpreted as scalar glueball. Its mass and width are determined to $M=1865$\er25$^{+10}_{-30}$ {\rm MeV} and $\Gamma= 370$\er$50^{+30}_{-20}$ {\rm MeV}, its yield in radiative $J/\psi$ decays to ($5.8\pm 1.0)\,10^{-3}$.