E. Barzi

Properties of photon plus two-jet events in {ovr p}p collisions at {radical}{ovr s}= 1.8 TeV.

We present the first general measurements (invariant-mass, transverse-energy, and angular distributions) of the process, {bar p}p{r_arrow}{gamma}+2 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. {copyright} {ital 1997} {ital The American Physical Society}