Confirmation of the 1−+ meson exotics in the ηπ0 system

The exclusive reaction π−p→ηπ0n, η→π+π−π0 at 18GeV/c has been studied with a partial wave analysis on a sample of 23 492 ηπ0n events from BNL experiment E852. A mass-dependent fit is consistent with a resonant hypothesis for the P+ wave, thus providing evidence for a neutral exotic meson with JPC=1−+, a mass of 1257±20±25MeV/c2, and a width of 354±64±60MeV/c2. New interpretations of the meson exotics in neutral ηπ0 system observed in E852 and Crystal Barrel experiments are discussed.