Electroweak baryogenesis in supersymmetric models

The baryon density which may be produced during the electroweak phase transition in supersymmetric models is computed, taking into account the previously neglected effects of transport, strong and weak anomalous fermion number violation, thermal scattering, and a new method for computing CP-violating processes during the transition. We can account for the observed baryon asymmetry, provided new CP-violating phases are greater than ∼${10}^{\mathrm{-}2}$–${10}^{\mathrm{-}4}$, and some superpartners are light enough to be relevant during the transition, which takes place at a temperature of 50–100 GeV. In one case, the light superpartners are the top squarks and the charginos and/or the neutralinos; in another case the top squarks and both Higgs doublets are light. Our calculation is easily extended to the case of a general two Higgs model, where we find sufficient baryogenesis provided that a certain combination of parameters in the Higgs potential leads to a CP-violating space-dependent phase in the top quark mass of order ${10}^{\mathrm{-}3}$. © 1996 The American Physical Society.