Speaker
Description
A strong first-order electroweak phase transition (EWPT) can be realized through the introduction of a light scalar that is weakly coupled to the Higgs boson. Such weak couplings can result in a macroscopic lifetime, leading to displaced decays that provide a distinctive experimental signature. In this talk, we investigate the sensitivity of future lepton colliders to long-lived scalars "s" produced in Higgs decays through e^+e^- -> ZH, with H -> ss and the scalars decaying at displaced vertices. Using realistic detector simulation, we develop a selection-based analysis and explore machine learning methods using detector level information to further improve the sensitivity. Our results demonstrate the potential of long-lived particle searches at future lepton colliders to provide a new probe of EWPT physics.
