# Phase transition and effect on leptogenesis

What is the effect on leptogenesis in the standard model if the electroweak phase transition is (i) first order and (ii) second order?

Considering leptogenesis $\Delta L \neq 0$ we need a first order PT, since non-equilibrium is one of the Sakharov conditions required for leptogenesis. If these conditions are fulfilled, sphaleron processes violate lepton (or baryon) number by "jumping" from the symmetric $(\phi = 0)$ to the broken $(\phi=\phi_0)$ phase. I found this plot: (Never mind the numbers, in the case of EWPT the critical temperature $T_c \sim \mathcal{O}(100 GeV)$ )