DYNAMICS OF 2-HIGGS-DOUBLET CP VIOLATION AND BARYOGENESIS AT THE ELECTROWEAK PHASE-TRANSITION

We quantitatively study the charge transport mechanism of electroweak baryogenesis in a realistic two-Higgs-doublet model, comparing the con tributions;from quarks and leptons reflecting from electroweak domain walls, and comparing the exact profile of the CP-violating phase with a commonly used ansatz. We note that the phenomenon of spontaneous CP violation at high temperature can occur in this model, even when there is no CP violation at zero temperature. We include all known effects which are likely to influence the baryon production rate, including st rong sphalerons, the nontrivial dispersion relations of the quasiparti cles in the plasma, and Debye screening of gauged charges. We confirm the claim of Joyce, Prokopec, and Turok that the reflection of tau lep tons from the wall gives the dominant effect. We conclude that this me chanism is at best marginally capable of producing the observed baryon asymmetry of the universe, and we discuss some ways in which it might be enhanced.