Properties of the Neutral Kaon(s) Neutral Kaon(s) Neutral Pion System Produced in Negative Pion-Proton Interactions at 21 Gev/c.

The exclusive nK^0_{ rm S}K^0_{ rm S}pi^0 channel has been investigated in 21 GeV/c pi^-p scattering. A total of 6265 events have been identified. The resulting K^0_{rm S} K^0_{rm S} pi^0 effective mass distribution indicates the production of resonances in the D(f_1 (1285)) and E(eta(1425)/ iota(1440)) meson regions. Both resonances are found to be produced with a broader t distribution than is observed for the higher mass background. Mass and width of the D region resonance are consistent with accepted values for the D meson. The E region is consistent with production of a single wide resonance whose parameters are the same as those of the iota(1440), but can also be fitted with two resonance peaks. Spin and parity have been analysed using the Zemach tensor method to perform maximum likelihood fits to Dalitz plots. This analysis confirms a 1^{++} assignment for the D meson, and indicates the production of a 0^{-+} resonance over a quickly rising, nonresonant 1^{++ } background in the E region. The 0 ^{-+} contribution in the E region is enhanced relative to the 1^{++} when events with t^' > 0.2 GeV^2 are selected.