Study of the ηη system in the π−p charge exchange reaction at 32 GeV/c with the GAMS-4π spectrometer

A study has been made of the ηη system produced in the π−p charge exchange reaction at 32 GeV/c. The experiment was performed at the IHEP 70‐GeV proton synchrotron with the GAMS‐4π spectrometer. A partial wave analysis has been carried out in the mass range from 1.1 to 3.9 GeV with −t < 0.2 (GeV/c)2 including the waves S, D0, D−, D+, G0, G− and G+. Three states are unambiguously observed in the S‐wave: f0(1370) , f0(1500), and f0(1710). The large accumulated statistic allows to resolve the G(1590) structure into two separate states the f0(1500) and the f0(1710). Two states f0(2100) and f2(1950) are observed in one solution. The f4(2050) is seen in the G0‐wave. A new spin 4 structure observed in the region above 2.7 GeV/c2. This state needs further investigation due to the possible influence of a spin 6 state.