The two-loop finite-temperature effective potential of the MSSM and baryogenesis

We construct an effective three-dimensional theory for the MSSM at high temperatures in the limit of large-mA. We analyse the two-loop effective potential of the 3D theory for the case of a light right-handed stop to determine the precise region in the mh−mtR plane for which the sphaleron constraint for preservation of the baryon asymmetry is satisfied. We also compare with results previously obtained using 3D and 4D calculations of the effective potential. A two-stage phase transition still persists for a small range of values of mtR. The allowed region requires a value of mtr ⪅ mt and mh ⪅ 100 (100) GeV for mQ = 300 GeV (1 TeV).