Hadroproduction of t anti-t pair in association with an isolated photon   at NLO accuracy matched with parton shower
  We simulate the hadroproduction of a t anti-t pair in association with a hard photon at LHC using the PowHel package. These events are almost fully inclusive with respect to the photon, allowing for any physically relevant isolation of the photon. We use the generated events, stored according to the Les-Houches event format, to make predictions for differential distributions formally at the next-to-leading order (NLO) accuracy and we compare these to existing predictions accurate at NLO using the smooth isolation prescription of Frixione. We also make predictions for distributions after full parton shower and hadronization using the standard experimental cone-isolation of the photon. 
Adam Kardos and Zolt\'an Tr\'ocs\'anyi
hep-ph