Asymmetries between the production of D+ and D- mesons from 500 GeV/c   pi- nucleon interactions as a function of xF and pt**2
  We present asymmetries between the production of D+ and D- mesons in Fermilab experiment E791 as a function of xF and pt**2. The data used here consist of 74,000 fully-reconstructed charmed mesons produced by a 500 GeV/c pi- beam on C and Pt foils. The measurements are compared to results of models which predict differences between the production of heavy-quark mesons that have a light quark in common with the beam (leading particles) and those that do not (non-leading particles). While the default models do not agree with our data, we can reach agreement with one of them, PYTHIA, by making a limited number of changes to parameters used. 
E.M.Aitala, S.Amato, J.C.Anjos, J.A.Appel, M.Aryal, D.Ashery, J.   Astorga, S.Banerjee, I.Bediaga, G.Blaylock, S.B.Bracker, ...