Inclusive production of charged hadrons and K0S mesons in photon-photon collisions

The production of charged hadrons and KS0 mesons in the collisions of quasi-real photons has been measured using the OPAL detector at LEP. The data were taken at e+e- centre-of-mass energies of 161 and 172 GeV. The differential cross-sections as a function of the transverse momentum and the pseudorapidity of the charged hadrons and KS0 mesons have been compared to the leading order Monte Carlo simulations of PHOJET and PYTHIA and to perturbative next-to-leading order (NLO) QCD calculations. The distributions have been measured in the range 10<W<125 GeV of the hadronic invariant mass W. By comparing the transverse momentum distribution of charged hadrons measured in γγ interactions with γ-proton and meson-proton data we find evidence for hard photon interactions in addition to the purely hadronic photon interactions. (orig.)