The K0sK0s Final State in Two-Photon Collisions and Some Implications   for Glueball Searches
  The K0sK0s final state in two-photon collisions is studied with the L3 detector at LEP using data at centre of mass energies from 91 GeV to 183 GeV. The K0sK0s mass spectrum is dominated by the formation of the f_2'(1525) tensor meson whose two-photon partial width is measured. Clear evidence for destructive f_2-a_2 interference is observed. No signal is present in the region around 2.2 GeV. An upper limit for the two-photon partial width times the K0sK0s branching ratio of the \xi(2230) glueball candidate is then derived. An enhancement is observed around 1750 MeV. It may be due to the formation of a radial recurrence of the f_2'(1525) or to the s\bar{s} member of the 0++ meson nonet. 
Saverio Braccini