The nuclear dependence for 800 GeV/c proton production of neutron D mesons has been measured near ${\mathit{x}}_{\mathit{F}}$=0 in Experiment 789 at Fermilab. D mesons from beryllium and gold targets were detected with a pair spectrometer and a silicon vertex detector via their decay D→Kπ. No nuclear dependence is found, with a measured α=1.02±0.03±0.02. The measured differential cross section, dσ/${\mathit{dx}}_{\mathit{F}}$, for neutral-D-meson production at 〈${\mathit{x}}_{\mathit{F}}$〉=0.031 is 58±3±7 μb/nucleon. The integrated cross section obtained by extrapolation of the measured cross section to all ${\mathit{x}}_{\mathit{F}}$ is 17.7±0.9±3.4 μb/nucleon and is consistent with previous measurements.

• Received 16 December 1993

DOI:https://doi.org/10.1103/PhysRevLett.72.2542