New physics in resonant production of Higgs boson pairs

Introduction. The discovery of the 125 GeV Higgs boson at the LHC marks the successful completion of the long quest to validate the spontaneous breaking of the Standard Model (SM) gauge symmetry. The discovery intensies the search for new physics at the TeV scale using this Higgs particle as a probe. The Higgs branching fractions have been measured in many channels, with the best determinations in h! , h! ZZ ! ‘ + ‘ ‘ + ‘ , h ! WW ! ‘ + ‘ , and (to a lesser extent) in h! b b; + [1, 2]. The h couplings to t t and gg have been inferred from the cross sections and the total Higgs width has been bounded above the SM prediction. [1{5]. Although all evidence to date is consistent with the SM Higgs sector, LHC14 is quickly approaching. The precision of Higgs coupling measurements may reach a level at which the presence of new physics contributions is evident, and an International Linear Collider could provide still greater precision [4, 5]. However, new physics may be dicult to detect in single Higgs production, for ex