Three photon production to NLO+PS accuracy at the LHC
  In this paper, we present the next-to-leading order predictions for three photon production in the Standard Model, matched to the parton shower using the MC@NLO formalism. We have studied the role of parton shower on various observables and shown a selection of results for the 14 TeV LHC. 
M. K. Mandal, Prakash Mathews, V. Ravindran, Satyajit Seth
hep-ph hep-ex