ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2002, vol. 65, p. -
Study of the ππ mass spectra in the process e+e - → π+π-π0 at √s≃1020 MeV
The invariant mass spectra of the π+π- and π±π0 pairs in the process e+e - → π+π-π0 were studied in the Spherical Neutral Detector experiment at the VEPP-2M collider in the energy region √s≃1020 MeV. These studies were based on about 0.5×106 events. The spectra were analyzed in the framework of the vector meson dominance model. It was found that the experimental data can be described assuming the e+e-→ ρπ →π+π-π0 transition only. An upper limit on the branching ratio of the φ(1020)→π+π -π0 decay through intermediate states different from ρπ was obtained at the 90% confidence level: B(φ? →π+π-π0)<6 × 10 -4. The ρ-meson mass and width which follow from the spectra analysis are mρ=775.0±1.3 MeV, Γρ = 150.4±3.0 MeV. The mass difference of the neutral and charged ρ mesons was found to equal mρ± -mρ0 = -1.3 ± 2.3 MeV. In the π+π- mass spectrum the ρ-ω interference was seen at a two standard deviation level. © 2002 The American Physical Society.