Probe Higgs boson pair production via the 3l2j plus ∋ mode

We perform a detailed hadron-level study on the sensitivity of Higgs boson pair production via the WW*WW* channel with the final state 3l2j + is not an element of at the LHC with the collision energy root s = 14 TeV and a future 100 TeV collider. To avoid the huge background from pp -> ZW + jet processes, we confine to consider the four-lepton patterns: e(+/-)e(+/-)mu(+/-) and mu(+/-)mu(+/-)e(+/-). We propose a partial reconstruction method to determine the most reliable combination. After that, we examine a few crucial observables which can efficiently discriminate signal and background events, especially we notice that the observable m(T2) is very efficient. For the LHC 14 TeV collisions, with an accumulated 3000 fb(-1) data set, we find that the sensitivity of this mode can reach up to 1.5 sigma for the Standard Model and the triple coupling of Higgs boson lambda(3) in the simplest effective theory can be constrained into the range [-1, 8] at 95% confidence level; at a 100 TeV collider with the integrated luminosity 3000 fb(-1), the sensitivity can reach up to 13 sigma for the Standard Model and we find that all values of lambda(3) in the effective theory can be covered up to 3 sigma even without optimizing signals. To precisely measure the triple coupling of Higgs boson lambda(3) = 1 of the Standard Model at a 100 TeV collider, by using the invariant mass of three leptons which is robust against the contamination of underlying events and pileup effects and by performing a chi(2) analysis, we find that it can be determined into a range [0.8, 1.5] at 95% confidence level.