SPHALERON TRANSITIONS IN THE SYMMETRICAL PHASE OF THE STANDARD MODEL

Using a massive pure gauge theory with a dynamically generated magnetic mass approximately g2T as an effective theory of the standard model at high temperatures we estimate the rate of B+L violating processes in the symmetric phase. Treating the magnetic mass as a parameter of the theory we find a small range of mass values for which it is possible to apply steepest descent methods and to obtain transition rates larger than the expansion rate of the universe. However, the largest rate that can possibly occur in this model lies in a range where the saddle-point approximation breaks down and is by at least one order of magnitude smaller than those obtained by lattice simulations.