Comparison of the isolated direct photon cross sections in pp¯ collisions at s=1.8 TeV and s=0.63 TeV (original) (raw)

The cross section for isolated direct photon production in proton-antiproton collisions at center-of-mass energies of 1.8 TeV and 0.63 TeV was measured using the Collider Detector at Fermilab (CDF). Although the normalization of the measured data sets aligns with Quantum Chromodynamics (QCD) predictions for a transverse momentum (P_T) of 25 GeV/c, discrepancies were observed in the photon P_T distributions. This results in a significant disagreement in the ratio of cross sections in the scaling variable x_T, indicating potential gaps in conventional theoretical uncertainties such as scale dependence and parton distribution parameterizations.