The effects of Higgs boson couplings through HZZ production at future lepton colliders

TL;DR

This paper investigates the sensitivity of Higgs-gauge boson couplings at future lepton colliders using simulated HZZ production data within SMEFT, providing projected limits on specific coupling coefficients.

Contribution

It presents a detailed simulation-based analysis of Higgs couplings at future colliders, deriving new projected limits on SMEFT coefficients with realistic detector effects.

Findings

Best 95% CL limits on $ar{c}_{HB}$ and $ar{c}_{HW}$ at 3 TeV CLIC

Projected limits at 10 TeV Muon Collider

Comparison with current experimental bounds

Abstract

We focus on the sensitivity of the Higgs-gauge boson couplings at $H\gamma Z$ and $HZZ$ vertices through the process $\ell^- \ell^+ \rightarrow HZZ$ at CLIC and Muon Collider. Signal and relevant backgrounds events are generated in MadGraph within Standard Model Effective Field Theory (SMEFT) framework. These events are passed through Pythia for parton showering, and realistic detector effects are simulated by Delphes. The limits at 95% C.L. on the coefficients $\overline{c}_{HB}$ and $\overline{c}_{HW}$ are obtained at three b-tagging working points; loose, medium, and tight containing the Delphes card from CLIC and Muon Collider, corresponding to b-tagging efficiencies of 90%, 70%, and 50%, respectively. We report that our best 95% C.L. limits on $\overline{c}_{HB}$ and $\overline{c}_{HW}$ coefficients are $[-0.00098; 0.00047]$ and $[-0.00158; 0.00008]$, respectively, at 3 TeV CLIC with an integrated luminosity of 5 ab$^{-1}$, and $[-0.00021; 0.00019]$ and $[-0.00019; 0.00007]$, respectively, at 10 TeV Muon Collider with an integrated luminosity of 10 ab$^{-1}$. These limits are compared with the present experimental and various phenomenological limits.