The Sign of Gauge-Higgs Couplings at Future Lepton Colliders

This work investigates the capability of future lepton colliders to determine the sign of the gauge-Higgs coupling through the vector boson fusion (VBF) $Zh$ process. This channel offers a model-independent way to probe the sign of the gauge-Higgs coupling. Its sensitivity to interference effects and universal coupling with new physics makes it particularly effective. We show that a high-energy lepton collider such as CLIC can fully determine the sign of the gauge-Higgs coupling in a model-independent way and with high confidence.