Evidence for Axial-Vector and Pseudoscalar Resonances near 1.275 GeV inηπ+π−

Abstract

We present the first results from an isobar-model phase-shift analysis of the $\eta {\pi }^{+}{\pi }^{-}$ system. The $D\left(1275\right)\mathrm{}$ meson is established as a narrow ($\Gamma \sim 10$ MeV) $I{J}^P={01}^{+}$ resonance. Beneath the $D$ is a broader ($\Gamma \sim 70$ MeV) $I{J}^P={00}^{-}$ state which is a candidate for the radially excited $\eta$. The data are consistent with the existence of another 0$0^{-}$ object of comparable width near 1.4 GeV.