Event structure in photon plus two-jet final states

Direct photons can be used as a probe of the hard scattering mechanism in high-pT multi-jet states. For final states containing a photon and two jets, three classes of events can be distinguished according to whether the photon has the highest, second highest, or lowest energy as compared to the two jets. By comparing Dalitz plot structures as well as angular distributions for each of these different types of events, it is possible to distinguish the contributions from specific classes of Feynman graphs. In particular, it is possible to isolate a sample of events which is dominated by the bremsstrahlung production mechanism. (orig.)