Double Higgs boson production and Higgs self-coupling extraction at CLIC

Abstract

The Compact Linear Collider (CLIC) is a future electron–positron collider that will allow measurements of the trilinear Higgs self-coupling in double Higgs boson events produced at its high-energy stages with collision energies from sqrt{s} = 1.4 to 3 TeV. The sensitivity to the Higgs self-coupling is driven by the measurements of the cross section and the invariant mass distribution of the Higgs-boson pair in the W-boson fusion process, text {e}^{+}text {e}^{-}rightarrow {text {H}text {H}nu bar{nu }}. It is enhanced by including the cross-section measurement of ZHH production at 1.4 TeV. The expected sensitivity of CLIC for Higgs pair production through W-boson fusion is studied for the decay channels mathrm{b}bar{mathrm{b}}mathrm{b}bar{mathrm{b}} and mathrm{b}bar{mathrm{b}}mathrm{W}mathrm{W}^{*} using full detector simulation including all relevant backgrounds at sqrt{s} = 1.4 TeV with an integrated luminosity of mathcal {L} = 2.5 ab^{-1} and at sqrt{s} = 3 TeV with mathcal {L} = 5 ab^{-1}. Combining text {e}^{+}text {e}^{-}rightarrow {text {H}text {H}nu bar{nu }} and ZHH cross-section measurements at 1.4 TeV with differential measurements in text {e}^{+}text {e}^{-}rightarrow {text {H}text {H}nu bar{nu }} events at 3 TeV, CLIC will be able to measure the trilinear Higgs self-coupling with a relative uncertainty of -8% and +11% at 68% C.L., assuming the Standard Model. In addition, prospects for simultaneous constraints on the trilinear Higgs self-coupling and the Higgs-gauge coupling HHWW are derived based on the {text {H}text {H}nu bar{nu }} measurement.