D correlations in photoproduction

Kinematic correlations between the charmed D and D mesons produced by a photon beam of mean energy 100 GeVc have been measured by the NA142 experiment at CERN using a sample of almost background-free fully reconstructed DD events. The observed D and DD distributions are compared to the predictions of production models using different parameters for the charm fragmentation function and for the intrinsic transverse momentum of the partons.