K0sK0s Final State and Glueball Searches and Lambda-Lambdabar Production   in Two-Photon Collisions in L3 at LEP
  The K0sK0s final state in two-photon collisions is studied with the L3 detector at LEP using data collected at centre-of-mass energies from 91 GeV to 202 GeV. The mass spectrum is dominated by the formation of the f_2'(1525) tensor meson in the helicity two state. The two-photon width times the branching ratio is measured to be Gamma_{gamma gamma}(f_2'(1525))Br(f_2'(1525)->KKbar) = 0.076 +- 0.006 +- 0.011 keV. Clear evidence for destructive f_2(1270)-a_2(1320) interference is observed. In addition a clear signal for f_J(1750) is observed. The study of the decay angular distribution in the 1750 MeV mass region shows that the spin two helicity two wave is dominant. No signal is observed in the region around 2.2 GeV. The upper limit for the two-photon partial width of the \xi(2230) tensor glueball candidate of Gamma_{gamma gamma}(\xi(2230))Br(\xi(2230)->K0sK0s)<1.4 eV at 95% C.L. is derived. The production of Lambda-Lambdabar pairs in two-photon collisions is also studied. The cross section is compared to quark-diquark model predictions. 
Saverio Braccini