Observation of the π-p → ν'νn reaction and the search for a glueball

In order to search for scalar glueballs, a rare process, the eta' eta pair production in the charge-exchange π-p→eta'etan reaction has been selected and studied. The experiment was performed by means of the 38-GeV/c pion beam at the 70-GeV accelerator. The γ quanta from the decays eta' eta→4γ were detected by means of the hodoscope spectrometer GAMS-2000. The eta'eta system has been investigated in the mass range from the threshold up to 1.8 GeV. The mass spectrum and the angular distributions are in agreement with the production and the eta'eta-decay of the scalar G(1590) meson (a glueball candidate) which was observed earlier in the eta eta decay mode. The ratio of partial widths of G→eta' eta and G→eta eta decay channels is obtained to be 2.7+-0.8. This agrees with the value expected for a glueball