Probing EWPT in 2HDM with future lepton colliders

The electroweak phase transition can be made first order by extending the Standard Model (SM) Higgs sector with extra scalars. Here, we focus on the strong first-order electroweak phase transition (SFOEWPT) in the Type-II two Higgs doublet models (2HDMs). Through a parameter space scan, we find that SFOEWPT suggests upper limits on the masses of the heavy Higgs [Formula: see text], which is less than 1[Formula: see text]TeV. High-temperature expansion and Higgs vacuum uplifting are used for analytical understanding of our results. We find that sizeable loop corrections require [Formula: see text] to meet the SFOEWPT condition in the Type-II 2HDM. We also study the possibility of probing SFOEWPT at the one-loop level from Higgs and [Formula: see text]-pole precision measurements at future Higgs and [Formula: see text] factories.