Study of the KS0KS0 final state in two-photon collisions

Abstract The reaction e + e − → e + e − γ ∗ γ ∗ → e + e − K S 0 K S 0 is studied with the L3 detector at LEP and the formation of the f 2 ′(1525) resonance is observed. For an integrated luminosity of 114 pb −1 , 31±6 f 2 ′ events are found. Their angular distribution is consistent with a pure helicity two. The radiative width times the branching ratio is measured to be Γ γγ (f 2 ′)×Br(f 2 ′ → K K ) =(0.093±0.018±0.022) keV. Only three events are found in the f 2 (1270)−a 2 (1320) mass region, consistent with destructive f 2 −a 2 interference in the K S 0 K S 0 final state. The mixing angle of the tensor meson nonet is determined to the θ = (29.4 −1.6 +1.4 )°.