Improving Higgs coupling measurements through ZZ Fusion at the ILC

TL;DR

This paper assesses the potential of the ZZ fusion channel at the ILC for precise Higgs coupling measurements, demonstrating that it significantly enhances the accuracy of model-independent Higgs property determinations.

Contribution

It provides a realistic simulation-based analysis showing the importance of the ZZ fusion channel for Higgs measurements at the ILC, with improved precision over previous approaches.

Findings

Cross section can be measured to 2.9% accuracy with combined data.

Multivariate analysis improves measurement precision to 2.3%.

Highlights the significance of ZZ fusion in Higgs physics.

Abstract

We evaluate the $e^- e^+ \to e^- e^+ +h$ process through the $ZZ$ fusion channel at the International Linear Collider (ILC) operating at $500$ GeV and $1$ TeV center of mass energies. We perform realistic simulations on the signal process and background processes. With judicious kinematic cuts, we find that the inclusive cross section can be measured to $2.9\%$ after combining the $500$ GeV at $500 \text{fb}^{-1}$ and $1$ TeV at $1~ \text{ab}^{-1}$ runs. A multivariate log-likelihood analysis further improves the precision of the cross section measurement to $2.3\%$. We discuss the overall improvement to model-independent Higgs width and coupling determinations and demonstrate the use of different channels in distinguishing new physics effects in Higgs physics. Our study demonstrates the importance of the $ZZ$ fusion channel to Higgs precision physics, which has often been neglected in the literature.