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

Abstract The e + e − →e + e − K S 0 K ± π ∓ and e + e − →e + e − ηπ + π − 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 ± π ∓ final state shows an enhancement around 1470 MeV, which is identified with the pseudoscalar meson η (1440). This state is observed in γγ collisions for the first time and its two-photon width is measured to be Γ γγ (η(1440))× BR (η(1440)→ K K π)=212±50 ( stat. )±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 ηπ + π − channel the f 1 (1285) is observed, and upper limits for the formation of η (1440) and η (1295) are obtained.