A new view of the 0- and 2+ glueballs

Abstract

Data on $J/Ψ\to γ(ρρ)$ demand a broad $0^-$ $ρρ$ signal, attributable to a glueball with a mass of 1750--2100 MeV. Decays of this broad state to $ρρ$, $ωω$, $K^*\bar K^*$ and $ϕϕ$ channels agree well with flavour blindness. The narrow $ι(1440)$ may be attributed to mixing between the glueball and the $s\bar s$ radial excitation. The latter is pushed down in mass by repulsion between the two levels. We conjecture that the $2^+$ glueball may likewise be broad. Mixing between it and the $2^3P_2~q\bar q$ and $s\bar s$ radial excitation can explain the appearance of $f_2(1565)$ and a $2^+$ $Θ(1710)$ at masses lower than anticipated. Mixing with higher $q\bar q$ states can explain the $2^+$ resonance at 1920 MeV and also $ϕϕ$ signals observed by Etkin et al. and by the JETSET collaboration.