We report a measurement of the cross section for K 0 S pair production in single-tag two-photon collisions,GeV 2 , where Q 2 is the negative of the invariant mass squared of the tagged photon. The measurement covers the kinematic range 1.0 GeV < W < 2.6 GeV and j cos θ Ã j < 1.0 for the total energy and kaon scattering angle, respectively, in the γ Ã γ center-of-mass system. These results are based on a data sample of 759 fb −1 collected with the Belle detector at the KEKB asymmetric-energy e þ e − collider. For the first time, the transition form factor of the f 0 2 ð1525Þ meson is measured separately for the helicity-0, -1, and -2 components and also compared with theoretical calculations. We have derived the cross section for the process for W < 2.6 GeV from 121 signal candidate events. Finally, the γ Ã γ partial decay widths of the χ c0 and χ c2 mesons are measured as a function of Q 2 based on 10 candidate events in total.

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