Light resonances in K0SK±π∓ and ηπ+π− final states in γγ collisions at LEP

The $e^+ e^- \rightarrow e^+ e^- K^{0}_{s} K^{\pm} pi^{\mp}$ and $e^+ e^- \rightarrow e^+ e^- \eta \pi^{+} \pi^{-}$ final states are studied with the L3 detector at LEP using data collected at centre-of-mass energies from 183 GeV up to 202 GeV. The mass spectrum of the $K^{0}_{s} K^{\pm} \pi^{\mp}$ final state shows an enhancement around 1470 MeV, which is identified with the pseudoscalar meson $\eta(1440)$. This state is observed in $\gamma \gamma$ collisions for the first time and its two-photon width is measured to be $\Gamma_{\gamma\gamma}(\eta(1440)) x BR(\eta(1440) \rightarrow K\bar{K}\pi = 212 \pm 50 (stat) \pm 23 (sys)$ eV. Clear evidence is also obtained for the formation of the axial vector mesons $f_1$(1420) and $f_1$(1285). In the $\eta \pi^{+} \pi^{-}$ channel the $f_1$ (1285)} is observed, and upper limits for the formation of $\eta(1440)$ and $\eta(1295)$ are obtained.