Glueballs in Radiative $J/\psi$ Decays

TL;DR

This paper analyzes radiative $J/ar{psi}$ decays to identify and characterize glueball states, providing evidence for scalar and tensor glueballs through coupled-channel analysis and resonance fitting.

Contribution

It presents a detailed coupled-channel analysis of BESIII data, identifying scalar and tensor glueball candidates and discussing their properties and interpretations.

Findings

Scalar glueball observed with properties matching theoretical expectations.

Identification of tensor glueball candidates as high-mass resonances.

Possible pseudoscalar glueball signals in $J/ar{psi}$ decay data.

Abstract

The scalar glueball is observed in a coupled-channel analysis of the $S$-wave amplitude from BESIII data on radiative $J/\psi$ decays and further data. Ten scalar isoscalar resonances were required to fit the data. Five of them were interpreted as mainly-singlet, five as mainly-octet resonances in SU(3). The yield of resonances showed a striking peak with properties expected from a scalar glueball. The $D$ wave amplitude in the BESIII data on radiative $J/\psi$ decays reveales a high-mass structure which can be described by a single Breit-Wigner or by the sum of three $\phi\phi$ resonances interpreted as tensor glueballs a long time ago. The structure - and further tensor resonances observed in radiative $J/\psi$ decays - are tentatively interpreted as tensor glueball. In $J/\psi$ decays into $\gamma\pi^0\pi^0\eta'$ several resonances are reported. The possibility is discussed that the pseudoscalar glueball might be hidden in these data.