Revisiting electroweak phase transition with varying Yukawa coupling constants

We revisited the scenario of electroweak baryogenesis in the presence of large Yukawa couplings, in which it was previously found that a strongly first-order electroweak phase transition can occur. Given the sensitivity of the running of the Higgs quartic coupling on the Yukawa couplings, we find that large Yukawa couplings drastically lower the scale at which the Higgs potential becomes unstable. Specifically, with only two quarks having order one Yukawa coupling, the scalar potential becomes unstable at the TeV scale, assuming the standard model values for the Higgs sector parameters at the electroweak scale. Furthermore, if assuming the standard model values for the Higgs sector parameters at the TeV scale, the Higgs quartic coupling constant becomes too large at the electroweak scale. This in turn predicts a much lighter Higgs mass than the measured value of 125 GeV. The strength of the electroweak phase transition is also significantly weakened in this scenario.