Dissociation of the photon to π⁺π⁻π⁰π⁰ and ωπ⁰ states

Abstract

New measurements of 4π systems, produced by electron-positron annihilation and τ-decay, are analysed in terms of interfering contributions from two ρ′-mesons, ρ′₁ and ρ′₂, and from the tail of the ρ-meson decaying into two-body states. Separation into orthogonal 4π states, corresponding to different symmetrized isotopic spin wave-functions, is a central feature of the analysis. It is found that the major decay of the ρ′₁ is into a 4π state of class [31] and that the major production of 4π states of class [211] for 4π masses below 1.5 GeV is due to the tail of the ρ decaying to ωπ and, probably, toh ₁π. Nothing new can be inferred about the decays of ρ′₂, and specific needs for improved data are indicated.