Isolated Photon Cross Section in the Central and Forward Rapidity Regions inpp¯Collisions at√s=1.8TeV

A measurement of the cross section for production of single, isolated photons is reported for transverse energies in the range of 10–125 GeV for two regions of pseudorapidity, $|\eta |<0.9\mathrm{}$ and $1.6<\mathrm{}|\eta |<2.5\mathrm{}$. The data represent $12.9{\mathrm{pb}}^{-1\mathrm{}}$ of integrated luminosity accumulated in $\overline{p}p$ collisions at $\sqrt{s}=1.8\mathrm{}\mathrm{TeV}$ and recorded with the D0 detector at the Fermilab Tevatron Collider. The background, predominantly from jets which fragment to neutral mesons, is estimated using the longitudinal shower shape in the calorimeter. In both pseudorapidity regions the cross section is found to agree with the next-to-leading order QCD prediction for $30\lesssim E_T^{\gamma }\lesssim 80\mathrm{GeV}$.