Evidence for Two Pseudoscalar Resonances of the $\eta {\pi }^{+}{\pi }^{-}$ System in the $D\left(1285\right)\mathrm{}$ and $\frac{E}{\iota }$ Regions

High-statistics data on the reaction ${\pi }^{-}p\to \eta {\pi }^{+}{\pi }^{-}n$ at 8.06 GeV/c were obtained. An isobarmodel partial-wave analysis was performed for the $\eta \pi \pi$ system. The $\eta \mathrm{}\left(1275\right)\mathrm{}$ meson was confirmed as a narrow $I{J}^{\mathrm{PC}}={00}^{-+}$ resonance. It decays through both $\delta \pi$ and $\epsilon \eta$. A narrow state with $I{J}^{\mathrm{PC}}={00}^{-+}$ was found in an $\eta \pi \pi$ decay channel at 1.42 GeV. It has a prominent peak in a $\delta \pi$ decay mode. No significant $E\left(1420\right)\mathrm{}$ signal with $I{J}^{\mathrm{PC}}={01}^{++}$ was found near the mass region of 1.42 GeV.