Measurement of the charm production in gamma gamma interactions at LEP

The inclusive production of D*± mesons in two-photon collisions is measured with the ALEPH detector at e+e centre-of-mass energies from 183 GeV to 209 GeV. A total of 360 ± 27 D*± meson events are observed from an integrated luminosity of 699 pb -1 . Contributions from direct and singleresolved processes are separated using the ratio of the transverse momentum pt D*± of the D*± to the visible invariant mass Wvis of the event. Differential cross sections of D*± production as functions of pt D*± and the pseudorapidity |D*±| are measured in the range 2 GeV/c < pt D*± < 12 GeV/c and |D*±| < 1.5. They are compared to next-to-leading order (NLO) perturbative QCD calculations. The extrapolation of the integrated visible D*± cross section to the total charm cross section, based on the PYTHIA Monte Carlo program, yields (e+e→ e+ecc _ ) < s >=197 GeV = 731 ± 74stat ± 47syst ± 157extr pb.