The Two-Loop Finite-Temperature Effective Potential of the MSSM and Baryogenesis

Abstract

We construct an effective three dimensional theory for the MSSM at high temperatures in the limit of large-$m_A$. 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 $m_h$-$m_{{\tilde{t}}_R}$ plane for which the sphaleron constraint for preservation of the baryon asymmetry is satisfied. We also compare with results previously obtained usind 3D and 4D calculations of the effective potential. A two-stage phase transition still persists for a small range of values of $m_{{\tilde{t}}_R}$. The allowed region requires a value of $m_{{\tilde{t}}_R}\text{lsi}{m}_t$ and $m_h\text{lsi}100$ (110) GeV for $m_Q=300$ GeV (1 TeV).

Comments: 40 pages, 6 Postcsript figures, uses epsf