MELTING OF THE HIGGS VACUUM - CONSERVED NUMBERS AT HIGH-TEMPERATURE

We discuss the computation of the grand canonical partition sum descri bing hot matter in systems with the Higgs mechanism in the presence of non-zero conserved global charges. We formulate a set of simple rules for that computation in the high-temperature approximation in the lim it of small chemical potentials. As an illustration of the use of thes e rules, we calculate the leading term in the free energy of the stand ard model as a function of baryon number B. We show that this quantity depends continuously on the Higgs expectation value phi, with a cross over at phi similar to T where Debye screening overtakes the Higgs mec hanism-the Higgs vacuum ''melts''. A number of confusions that exist i n the literature regarding the B dependence of the free energy is clar ified.