Measurement of D*± cross sections in photon proton collisions at HERA

Open charm photoproduction has been studied with the ZEUS detector in electron proton collisions at the HERA collider at √(s)=300 GeV. The D*± → K-+π±π± decay mode has been measured using data taken in 1996 and 1997 which correspond to an integrated luminosity of L=16.6 pb-1. In the restricted phase space -1.0< η(D*) <1.5, 2.0 GeV< p perpendicularto (D*) <8.0 GeV, 80 GeV<W<120 GeV and Q2<0.15 GeV2 the total cross section was measured to σep→eD*X=8.8 ± 0.7(stat)-1.0+0.5(syst) nb. Differential cross sections have been measured as a function of p perpendicularto (D*) and η(D*). They are compared to different NLO QCD calculations. Within their limits of applicability the calculations are in reasonable agreement with the data. A slight excess of the cross section was found towards the proton direction. (orig.)