Evidence for an interference effect between ω and phi resonances in π+π-π0 production by e+e- annihilation

The cross section e+e-→π+π-π0 has been measured in the phi energy region and at three other energies (915, 990, 1076 MeV) chosen outside the ω and phi resonances. In the same experiment the energy position and the width of the phi resonance have been determined from the phi→K0sub(S)K0sub(L) channel. It is found that the magnitude and energy dependence of the experimental cross section are well described by coherent production of ω and phi in the whole energy range 770 to 1076 MeV. The data clearly show an interference effect which corresponds to an opposite sign between the two products gsub(γω)gsub(ω→3π) and gsub(γphi)gsub(phi→3π) of the coupling constants. (Auth.)