Study of the processe+e−→π+π−π0in the energy regionsfrom 0.98 to 1.38 GeV
Physical Review D, Particles and fields
The cross section of the process e^+e^-→π^+π^-π^0 was measured in the Spherical Neutral Detector experiment at the VEPP-2M collider in the energy region √(s) = 980 1380 MeV. The measured cross section, together with the e^+e^-→π^+π^-π^0 and ωπ^+π^- cross sections obtained in other experiments, was analyzed in the framework of the generalized vector meson dominance model. It was found that the experimental data can be described by a sum of ω, ϕ mesons and two ω^' and ω^" resonances
... with masses m_ω^'∼ 1490,m_ω^"∼ 1790 MeV and widths Γ_ω^'∼ 1210, Γ_ω^"∼ 560 MeV. The analysis of the π^+π^- invariant mass spectra in the energy region √(s) from 1100 to 1380 MeV has shown that for their descriptionone should take into account the e^+e^-→ωπ^0→π^+π^-π^0 mechanism also. The phase between the amplitudes corresponding to the e^+e^-→ωπ and e^+e^-→ρπ intermediate states was measured for the first time. The value of the phase is close to zero and depends on energy.