Two-pion decay mode of the and - mixing

Recent experiments reporting the 2 decay mode of the meson and its interference with that mode of the meson are analyzed in terms of the propagator method for mixing of particle states. Both vector mixing and mass mixing are included, and the energy dependence of the width is explicitly taken into account. It is shown that the effect as observed in the reaction e+e-+- can be accounted for in terms of available parameters. The consequent determination of the parameters makes possible an analysis of strong-interaction phenomena of the same type, giving information on the relative phases of and production amplitudes. This is applied to the - interference observed in +p+-++. Other experiments are suggested.