A strong electroweak phase transition in the 2HDM after LHC8

The nature of the electroweak phase transition in two-Higgs-doublet models is revisited in light of the recent LHC results. A scan over an extensive region of their parameter space is performed, showing that a strongly first-order phase transition favours a light neutral scalar with SM-like properties, together with a heavy pseudo-scalar (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$ {m_{{{A^0}}}} $\end{document} ≳ 400 GeV) and a mass hierarchy in the scalar sector, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$ {m_{{{H^{\pm }}}}}\lesssim {m_{{{H^0}}}}<{m_{{{A^0}}}} $\end{document}. We also investigate the h0 → γγ decay channel and find that an enhancement in the branching ratio is allowed, and in some cases even preferred, when a strongly first-order phase transition is required.