Double Higgs production at the 14 TeV LHC and a 100 TeV pp collider

We consider effective Higgs boson couplings, including both CP-even and CP-odd couplings, which affect Higgs boson pair production. Through partial wave analysis, we find that the process gg -> hh is dominated by the s-wave component even at a 100 TeV pp collider. Making use of s-wave kinematics, we propose a cut efficiency function to mimic the collider simulation and obtain the potential of measuring Higgs effective couplings at the 14 TeV LHC with an integrated luminosity of 3000 fb(-1) and at a 100 TeV pp collider. Analytical expressions of 2 sigma exclusion limits at the LHC and 5 sigma discovery bands at the 100 TeV machine are given.