The K0sK0s final state in two photon collisions and glueball searches

The K0sK0s final state in two photon collisions is studied with the L3 detector at LEP using data at center of mass energies from 91 GeV to 189 GeV. Four different mass regions in the K0sK0s invariant mass spectrum are investigated. The spectrum is dominated by the formation of the f'2(1525). The helicity and the two photon partial width of this state are measured. Destructive f2(1270)-a02(1320) interference is observed. There is no signal in the 2.2 GeV mass region. An upper limit for the two photon partial width times the K0sKos branching ratio of the ξ(2230) glueball candidate is then derived. An enhancement of 7 standard deviations is observed around 1750 MeV. This is consistent with a radial recurrence of the f'2(1525), however a contribution of JPC = 0++ cannot be excluded