Measurement of Direct Photon Cross Section in the Forward Pseudorapidity Region at do.

The production cross section of direct photons in the forward pseudorapidity region has been measured with the DO detector at the Fermilab Tevatron p | p Collider. The physics motivation, detecting techniques, and analysis methods are outlined. A cross section is presented, and compared to Next-to-Leading-Order Quantum Chromodynamics calculations. The cross section agrees with the theoretical prediction for transverse energy (E_{T}) values greater than 30 GeV. At lower E_{T} the shape of the cross section is steeper than what the theories indicate. The implications and a possible correction of this mismatch are discussed. Further extensions of this measurement are outlined.