A new view of the 0- and 2+ glueballs

Abstract

Data on $J/\Psi \to \gamma (\rho\rho)$ demand a broad $0^-$ $\rho\rho$ signal, attributable to a glueball with a mass of 1750--2100 MeV. Decays of this broad state to $\rho\rho$, $\omega\omega$, $K^*\bar K^*$ and $\phi \phi$ channels agree well with flavour blindness. The narrow $\iota(1440)$ 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 $2^+$ $\Theta (1710)$ at masses lower than anticipated. Mixing with higher $q\bar q$ states can explain the $2^+$ resonance at 1920 MeV and also $\phi \phi$ signals observed by Etkin et al. and by the JETSET collaboration.