Production of γ Z g and associated processes via gluon fusion at hadron colliders

We present results for the process $gg \to \gamma Z g$ within the standard model at hadron colliders. Due to large gluon flux at the LHC and the proposed HE-LHC, this process can have significant cross section at these machines. Several thousand such events have already been produced at the LHC according to the standard model predictions. This process can also be a background to new physics signals. We discuss some of the important features of this process related to the structure of its amplitude. We also compute the total cross section at the hadron colliders and give some important kinematic distributions. A comparison of our results is made with the corresponding NLO calculation using MCFM program. We briefly discuss the production of $\gamma \gamma g $ and $\gamma \gamma Z$ via gluon fusion. The amplitude of these processes are closely related to the $gg \to\gamma Z g$ amplitude.