Nuclear dependence of neutral-<i>D</i>-meson production by 800 GeV/<i>c</i>protons

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\ensuremath{\rightarrow}K\ensuremath{\pi}. No nuclear dependence is found, with a measured \ensuremath{\alpha}=1.02\ifmmode\pm\else\textpm\fi{}0.03\ifmmode\pm\else\textpm\fi{}0.02. The measured differential cross section, d\ensuremath{\sigma}/${\mathit{dx}}_{\mathit{F}}$, for neutral-D-meson production at 〈${\mathit{x}}_{\mathit{F}}$〉=0.031 is 58\ifmmode\pm\else\textpm\fi{}3\ifmmode\pm\else\textpm\fi{}7 \ensuremath{\mu}b/nucleon. The integrated cross section obtained by extrapolation of the measured cross section to all ${\mathit{x}}_{\mathit{F}}$ is 17.7\ifmmode\pm\else\textpm\fi{}0.9\ifmmode\pm\else\textpm\fi{}3.4 \ensuremath{\mu}b/nucleon and is consistent with previous measurements.