Isolated Photon Cross Section inpp¯Collisions at√s=1.8TeV

We report a new measurement of the cross section for the production of isolated photons with transverse energies ( $E_T^{\gamma }$) above 10 GeV and pseudorapidities $|\eta |<2.5\mathrm{}$ in $p\overline{p}$ collisions at $\sqrt{s}=1.8\mathrm{}\mathrm{TeV}$. The results are based on a data sample of $107.6{\mathrm{pb}}^{-1\mathrm{}}$ recorded during 1992–1995 with the D0 detector at the Fermilab Tevatron collider. The background, predominantly from jets which fragment to neutral mesons, was estimated using the longitudinal shower shape of photon candidates in the calorimeter. The measured cross section is in good agreement with the next-to-leading order QCD calculation for $E_T^{\gamma }\gtrsim 36\mathrm{GeV}$.