  A cosmological first order electroweak phase transition could explain the
origin of the matter-antimatter asymmetry in the Universe. Such a phase
transition does not occur in the Standard Model, while it becomes possible with
the existence of a second Higgs doublet in Nature. We obtain the properties of
the new scalars $H_0$, $A_0$ and $H^{\pm}$ that lead to such a phase
transition, showing that its characteristic signature at LHC would be the
observation of the decay $A_0 \rightarrow H_0 Z$. We analyze the LHC search
prospects for this decay in the $\ell \ell b\bar{b}$ and $\ell \ell W^{+}
W^{-}$ final states, showing that either one is promising at the early stages
of the 14 TeV run.
