Model-independent ZH production cross section at FCC-ee

TL;DR

This paper forecasts a highly precise, model-independent measurement of the ZH production cross section at FCC-ee, combining leptonic and hadronic decay modes using recoil-mass techniques at different energies.

Contribution

It introduces a comprehensive, combined analysis method for leptonic and hadronic Z decays, achieving unprecedented precision and demonstrating model independence at future lepton colliders.

Findings

Relative precision of 0.52% at 240 GeV for leptonic channels

Total uncertainty of 0.31% at 240 GeV

Demonstrated model independence within statistical precision

Abstract

This paper presents prospects for a model-independent measurement of the $ZH$ production cross section at the FCC-ee using the recoil-mass technique at center-of-mass energies of $\sqrt{s}=240$ and $365$ GeV. The analysis considers the muon, electron, and hadronic decay modes of the associated $Z$ boson. Event selections rely primarily on the kinematic properties of the reconstructed $Z$ decay products, ensuring maximal independence from specific Higgs boson decay modes, while multivariate techniques are employed to further enhance sensitivity. Statistical interpretations of the individual final states yield relative precisions of $0.52\%$ for the combined leptonic channels and $0.38\%$ for the hadronic channel at $\sqrt{s}=240$ GeV with an integrated luminosity of $10.8$ ab$^{-1}$. Their full statistical combination leads to total uncertainties of $0.31\%$ at $\sqrt{s}=240$ GeV and $0.52\%$ at $\sqrt{s}=365$ GeV with $3.12$ ab$^{-1}$. Dedicated statistical tests demonstrate model independence at the level of the obtained precision. This study presents, for the first time, a consistent and combined analysis of the leptonic and hadronic final states, achieving the most precise projected determination of the $ZH$ production cross section at future lepton colliders, with model independence demonstrated within the statistical precision.