Glueballs

The current status of various glueball properties such as level ordering, masses, production, and decay is reviewed. Glueball candidates iota(1440), theta(1670), g/sub T/(2160), g/sub T/(2320), and 0(2.3-3.4) are examined. A simple model which incorporates the mixing of the glueball candidate iota(1440) with quarkonium states eta(549) and eta'(958), and of the theta(1670) with f(1270) and f'(1515) is presented; neither the iota(1440) nor the theta(1670) can be consistently interpreted as a glueball in this framework. A 5 x 5 model of Palmer and Pinsky which also includes radial excitation of the eta an eta' yields two solutions for the pseudoscalar system, the preferred one of which has iota(1440) being mainly an ss-bar radial excitation, and a second solution in which the iota(1440) is mixed strongly with the eta'(960) and is about half bare glueball. The current leading glueball candidates are the phiphi enhancements at 2160 and 2320 MeV