THERMODYNAMICS OF THE ELECTROWEAK PHASE TRANSITION

We discuss several general aspects of the free energy of the standard model at high temperatures. In particular the Clausius-Clapeyron equation is shown to yield a relation between the latent heat and the jump in the order parameter. The free energy is calculated as function of temperature in resummed perturbation theory to two-loop order. A new resummation procedure is proposed in which the symmetric phase and the Higgs phase are treated differently. A quantitative description of the phase transition is achieved for Higgs masses below $\sim 70$ GeV. The results are found to be in agreement with recent numerical simulations on large lattices. The phase transition provides no evidence for strong non-perturbative effects in the symmetric phase.