Probing the trilinear Higgs boson coupling in di-Higgs production at NLO QCD including parton shower effects

We present results for Higgs boson pair production with variations of the trilinear Higgs boson self coupling at next-to-leading order (NLO) in QCD including the full top quark mass dependence. Differential results for the LHC at 14 TeV are presented and we discuss the implications of anomalous trilinear couplings as well as differences between the Pythia and Herwig parton showers in combination with POWHEG. The implementation of the NLO QCD calculation with variable Higgs boson self coupling is made publicly available in the POWHEG-BOX-V2 Monte Carlo framework. A simple method for using the new implementation to study also variations of the top quark Yukawa coupling is described.