Evidence for ϱπ dominance in φ --> 3 η decay

About seven hundred π⁺π^-π^o events produced by e⁺e^- annihilation at the φ meson energy are analysed by comparing the experimental Dalitz-plot to the distributions predicted by either a Lorentz invariant phase-space production of the three pions or by a dynamical φ-->ϱπ-->π⁺π^-π^o process as given by the Gellman-Sharp-Wagner model. The result gives clear evidence for ϱπ dominance.