P. Minkowski1 - W. Ochs2
1 Institute for Theoretical Physics,
University of Bern,
CH-3012 Bern, Switzerland
2 Max Planck Institut für Physik, Werner Heisenberg Institut, D-80805 München, Germany
Received: 30 November 1998 / Revised version: 17 February 1999 / Published online: 27 April 1999
We discuss the theoretical expectations and phenomenological evidence for the lightest glueballs and the members of the meson nonet with quantum numbers JPC=0++. We reconsider the recent evidence for candidate states with masses below 1700 MeV, but include also the results from earlier phase-shift analyses. Arguments are presented to classify the scalars f0(980) and f0(1500) as members of the 0++ nonet, with a mixing rather similar to that of the pseudoscalars and . The S-wave states called f0(400-1200) and f0(1370) are considered as different signals from a single broad resonance, which we take to be the lowest-lying 0++ glueball. This state together with and fJ(1710) with spin J=2 form the basic triplet of binary gluonic bound states. We argue that these hypotheses are consistent with what can be expected theoretically.