Direct photon production has been studied by an experiment performed with the NA3 spectrometer at CERN, using incident negative and positive beams at 200 GeV/c interacting with an isoscalar Carbon target. Two different triggers have been used; one of them requires the photon conversion. The experiment is sensitive to direct photons produced with 3.0≦PT≦6 GeV/c and center-of-mass rapidity −0.4≦y*≦1.2. Inclusive cross sections are given for incident π± and protons, and compared with second order QCD predictions; finally an estimation of the gluon structure function of the nucleon is given.
Data from conversion trigger. Statistical errors only.
Data from calorimeter trigger. Statistical errors only.