INTERFERENCE IN THE REACTION E(-)-]GAMMA-PI(+)PI(-) FINAL-STATE INTERACTION()E()

Interference between the amplitudes of the reactions e(+)e(-) --> rho --> y pi(+)pi(-) and e(+)e(-) --> phi --> gamma(f(0) + sigma) --> gamm a pi(+)pi(-) is considered with allowance for the phase of an elastic background and for the phase of the mixing of the f(0) and sigma meson s. It is shown that, in the reaction e(+)e(-) --> rho --> gamma pi(+)p i(-), the Fermi-Watson theorem for final-state interaction is inapplic able in the case of soft photons (omega < 100 MeV) in the phi-meson re gion. Interference patterns are obtained in the differential cross sec tions with respect to photon energies and in the total cross section a s a function of the beam energy.