Partial wave analysis of J/ψ→γ(K+K−π+π−)

Abstract BES data on J / ψ → γ ( K ± K S 0 π ∓ ) are presented. There is a strong peak due to η (1440)/ ι , which is fitted with a Breit–Wigner amplitude with s -dependent widths for decays to K ∗ K , κK , ηππ and ρρ ; κ refers to the Kπ S-wave. At a K K π mass of ∼2040 MeV, there is a second peak with width ∼400 MeV; J P =0 − is preferred over 1 + and 2 − respectively by 5.2 and 6.8 standard deviations. It is a possible candidate for a 0 − s s g hybrid partner of π (1800).