Sphalerons in the MSSM

We construct the sphaleron solution, at zero and finite temperature, in the Minimal Supersymmetric Standard Model as a function of the supersymmetric parameters, including the leading one-loop corrections to the effective potential in the presence of the sphaleron. At zero temperature we have included the one-loop radiative corrections, dominated by the top/stop sector. The sphaleron energy E_MSSM mainly depends on an effective Higgs mass m_h^eff = lim _{mA≫ mw}mh, where m_h is the lightest CP-even Higgs mass and m_A the pseudoscalar mass. We have compared it with the Standard Model result, with m_h^SM = m_h^eff, and found small differences (1-2%) in all cases. At finite temperature we have included the one-loop effective potential improved by daisy diagram resummation. The sphaleron energy at the critical temperature can be encoded in the temperature dependence of the vacuum expectation value of the Higgs field with an error ≲ 10%. The light stop scenario has been re-examined and the existence of a window where baryon asymmetry is not erased after the phase transition, confirmed. Although large (low) values of m_h ( m_A) are disfavored by the strength of the phase transition, that window (along with LEP results) allows for m_h ≲ 80 GeV, m_A ≳ 110 GeV and A_t ≲ 0.4 m_Q.