Study of the process e+e−→ωπ0 in the ϕ-meson mass region with the KLOE detector

We have studied the e + e − → ω π 0 cross section in the s interval 1000–1030 MeV using the π + π − π 0 π 0 and π 0 π 0 γ final states with a sample of ∼ 600 pb −1 collected with the KLOE detector at DAΦNE. By fitting the observed interference pattern around M ϕ for both final states, we extract the ratio of the decay widths Γ ( ω → π 0 γ ) / Γ ( ω → π + π − π 0 ) = 0.0897 ± 0.0016 and derive the branching fractions BR ( ω → π + π − π 0 ) = ( 90.24 ± 0.19 ) % , BR ( ω → π 0 γ ) = ( 8.09 ± 0.14 ) % . The parameters describing the e + e − → π + π − π 0 π 0 reaction around M ϕ are also used to extract the branching fraction for the OZI and G-parity violating ϕ → ω π 0 decay: BR ( ϕ → ω π 0 ) = ( 4.4 ± 0.6 ) × 10 −5 .