Glueballs in Radiative $J/\psi$ Decays

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 $\varphi \varphi$ 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 $\gamma {\pi }^0{\pi }^0{\eta }^{\prime }$ several resonances are reported. The possibility is discussed that the pseudoscalar glueball might be hidden in these data.

Comments: Contribution to XVth Quark confinement and the Hadron spectrum conference, August 1st - 6th, 2022, University of Stavanger, Norway