The current picture of Glueballs

Abstract

Some recent developments in the phenomenology of the lightest scalar glueball are summarised. Tools for determining the gluonic content of a resonance of known mass, width and $J^{PC}$ from its branching fraction in radiative quarkonium decays and production cross section in $\gamma \gamma$ collisions are presented. Two $q\bar{q}-G$ mixing schemes for $J^{PC}=0^{++}$, inspired by the lattice, are shown to lead to similar phenomenology that may be tested at BEPC and in $\gamma \gamma$ production at LEP2.

Comments: Rapporteur talk at LEAP96, Dinkelsbuhl, Germany; 27-31 Aug 1996 (based on work with C.Amsler, with G.Farrar and Z.P.Li, and with M.Teper)