Observation of a new JPC=1 +− isoscalar state in the reaction π−p→ ωηn at 18 GeV/ c

Abstract

Results are presented on a partial wave analysis of the ωη final state produced in π − p interactions at 18 GeV/ c where ω→ π + π − π 0, π 0→2 γ , and η→2 γ. We observe the previously unreported decay mode ω(1650)→ ωη and a new 1 +− meson state h 1(1595) with a mass M=1594(±15) +10 −60 MeV/ c 2 and a width Γ=384(±60) +70 −100 MeV/ c 2. The h 1(1595) state exhibits resonant-like phase motion relative to the ω(1650).