Investigation of the ηη system in π-p interactions at a momentum of 32.5 GeV/c at the GAMS-4π spectrometer

The ηη system produced in charge-exchange π−p interaction at a momentum of 32.5 GeV/c is studied in an experiment performed with the GAMS-4π spectrometer at the 70-GeV accelerator of the Institute for High-Energy Physics (IHEP, Protvino). A partial-wave analysis is performed in the mass range between 1.1 and 3.9 GeV for −t <0.2 (GeV/c)2, S, D, G, and J waves being taken into account in this analysis. The S wave has a complicated structure, displaying peaks at about 1.5 and 1.7 GeV. These peaks are associated with the f0(1500) and f0(1710) mesons. One of the solutions (preferable one) involves the f0(2200) and f2(1950) resonances. The mass region above 2.4 GeV is dominated by the G wave. A broad state of mass about 3 GeV and width 0.7 GeV is found in the J wave. The parameters of the resonances in question and their production cross sections are measured.