Measurement of the inclusive D∗± production in γγ collisions at LEP

Abstract 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 single-resolved processes are separated using the ratio of the transverse momentum p t D ∗± the D ∗± to the visible invariant mass W vis of the event. Differential cross sections of D ∗± production as functions of p t D ∗± and the pseudorapidity |η D ∗± | are measured in the range 2 GEV /c t D ∗± GeV /c and |η D ∗ | . They are compared to next-to-leading order (NLO) perturbative QCD calculations. The extrapolation of the intergrated visible D ∗± cross section to the total charm cross section, based on the Pythia Monte Carlo program, yields σ(e + e − → e + e − c c ) 〈√s 〉=197 GeV = 731 ± 74 stat ± 47 syst ± 157 extr pb.