10. Meson spectroscopy

     The search for the tensor glueball is one of primary objectives of the meson spectroscopy in the mass region 1900-2400 MeV. There are rather strong proofs that the scalar glueball exists with mass 1500-1650 MeV. It mixes with nearby states and physical resonances carry a large content of this state. The lattice QCD calculations give the ratio of tensor and scalar glueball masses ~ 1.4 with rather small errors. It corresponds to a mass for the tensor glueball 2150-2350 MeV. The first step in the tensor glueball search is to locate meson resonances in this mass region. The indication of an exotic state could be an appreciable deviation of the pole positions from the linear trajectories or the presence of a state which does not match linear trajectories at all. The real progress was made in the analysis of new data on annihilation in flight taken by Crystal Barrel collaboration at LEAR over the momentum range of antiproton 600-1940 MeV/c. The neutral particle production channels were analyzed by PNPI (Theoretical Physics Division and High Energy Physics one) group in collaboration with D.V.Bugg (Queen Mary and Wiestfield college, London), B.S.Zou (IHEP, Beijing) and group of C.Batty from Rutherford Appleton Laboratory (England). The following final neutral channels have been processed: ; ; ;; .
     The first stage was a separate partial wave analysis of two body and three body final states. At the next stage all relevant data production channels were investigated in the framework of a combined analysis. The analysis allows us to determine a considerable number of meson states over the range 1900-2400 MeV that makes it possible to carry out the systematics of states in the (n, M2) and (J, M2) planes.

Historical overview of main activities