Higgs boson decays to invisible at the Future $e^+e^-$ Circular Collider (FCC-ee)

The study of the Higgs boson's invisible decay is a key process at the Future Circular Collider (FCC-ee), as many models of new physics predict contributions beyond the Standard Model (SM) decay channel H->ZZ->4ν. The electron-positron collision environment at the FCC-ee provides a unique opportunity to reconstruct unobserved Higgs boson decays through energy-momentum conservation, which is sensitive to both detector design and simulation fidelity.

This work investigates the Higgs invisible decay channel through two approaches. First, a comparison is conducted between fast simulation for the IDEA detector and full simulation for the CLD detector, incorporating both signal and primary backgrounds. This allows for a detailed examination of the differences between fast and full simulation techniques. Second, using fast simulation, we evaluate the impact of calorimeter property variations within the IDEA detector on the precision of this measurement. This study provides insights into the detector sensitivities essential for optimizing Higgs boson measurements at the FCC-ee.