Measurement of single spin asymmetry for direct photon production in pp collisions at 200 GeV/c

The single spin asymmetry for inclusive direct-photon production has been measured using a polarized proton beam of 200 GeV/c with an unpolarized proton target at -0.15 < x(F) < 0.15 and 2.5 < p(T) < 3.1 GeV/(c) at Fermilab. The data on the cross section for pp --> gamma X at 2.5 < p(T) < 3.8 GeV/c are also provided. The measurement was done using lead-glass calorimeters and photon detectors which surrounded the fiducial area of the calorimeters. Background rejection has been done using these surrounding photon detectors. The cross section obtained is consistent with the results of previous measurements assuming a nuclear dependence of A(1.0). The single spin asymmetry, A(N), for the direct-photon production is consistent with zero within experimental uncertainty.