Resonances around 2 GeV: q(q)over-bar and glueballs

Crystal Barrel data reveal systematics of q (q) over bar resonances up to 2410 MeV. In particular, all expected J(PC) = 2(++) 1 = 0 q (q) over bar states may be identified in this range of masses M. For most J(PC), observed resonances lie close to straight line trajectories of M-2 v. radial quantum number, all having a uniform slope of 1.1 +/- 0.03 GeV2 per excitation. Tensor and spin-orbit splitting is small. Resonances with L = J + 1 lie similar to 100 MeV higher in mass than those with L = J - 1. Several states remain which do not fit naturally into this scheme, notably f(0)(1500), f(0)(2105), a broad 2(+) state at 1980 +/- 50 MeV and a broad 0(-) resonance at 2190+/-40 MeV. Their mass ratios agree within small errors (3-14%) with Lattice QCD calculations of Morningstar and Peardon for glueballs. The f(0)(2105) appears strongly in the eta eta channel, but not in pi pi. This indicates exotic character. If interpreted in terms of a mixed state cos Phi(u (u) over bar + d (d) over bar)/root 2 + sin Phi s (s) over bar, then Phi = (65 +/- 6)degrees.