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

## TL;DR

This paper evaluates CLIC's potential to measure the Higgs self-coupling via double Higgs production, demonstrating that with 5 ab$^{-1}$ at 3 TeV, it can determine the coupling with about 8-11% precision.

## Contribution

It provides a detailed sensitivity study of Higgs self-coupling measurement at CLIC, including full detector simulation and multiple production channels.

## Key findings

- CLIC can measure Higgs self-coupling with 8-11% precision at 3 TeV.
- Including ZHH production improves sensitivity.
- Full detector simulation confirms feasibility of the measurement.

## Abstract

The Compact Linear Collider (CLIC) is a future electron-positron collider that will allow measurement of the trilinear Higgs self-coupling in double Higgs boson events produced at its high-energy stages with collision energies of $\sqrt{s}$ = 1.5 and 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, e$^+$e$^-\to$HH$\nu_e \bar{\nu}_e$. It is enhanced by including the cross-section measurement of ZHH production at 1.5 TeV. The expected sensitivity of CLIC for Higgs pair production through W-boson fusion is studied for the decay channels bbbb and bbWW using full detector simulation including all relevant backgrounds. With an integrated luminosity of $\mathcal{L}$ = 5 ab$^{-1}$ at $\sqrt{s}$ = 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.