Meson Resonances in Proton-Antiproton Annihilation

Crystal Barrel data for proton-antiproton annihilation in flight at 900 MeV /c are presented. The channels pp → 3π0, π0π0η and π0ηη are used to search for isoscalar 0++ and 2++ mesons in the mass range 1500- 2000 MeV. Both 3π0 and π0ηη data sets require an isoscalar 2++ resonance decaying into π0π0 and ηη with mass M = (1867±46) MeV and width r = (385±58) MeV. The analysis of π0π0 leads to an isovector 2++ state decaying into π0η with mass M = (1698±44) MeV and width r = (265± 55) MeV. The 3π0 and π0ηη data do not show any fo(1710). This adds supportive evidence that this meson is mainly ss. (author)