Properties of photon plus two-jet events in p̄p collisions at √s = 1.8 TeV

We present the first general measurements (invariant-mass, transverse-energy, and angular distributions) of the process, $\overline{p}\stackrel{\ensuremath{\rightarrow}}{p}\ensuremath{\gamma}+2$ $\mathrm{jets}+X,$ using data collected by the CDF at Fermilab. We compare the data with predictions from a tree-level QCD calculation and the PYTHIA shower Monte Carlo program. Our data sample is particularly sensitive to contributions from initial- and final-state radiation of photons and jets. Using the PYTHIA Monte Carlo program, we contrast the kinematical distributions for direct photon production with those for initial- and final-state photon radiation (bremsstrahlung). Based on the angular distributions, we find that our data favor a mixture of bremsstrahlung and direct photon production, as predicted, over either process alone.