MSSM lightest CP-even Higgs boson mass to O (αsαt):: the effective potential approach

Starting with the two-loop effective potential of the MSSM, and assuming a supersymmetric scale well above M-Z, we derive a simple analytical approximation for the lightest CP-even Higgs boson mass including resummation of higher order logarithmic terms via RG-improvement and finite non-logarithmic terms up to O(alpha(s)alpha(t)). This formula describes the most relevant radiative corrections to the MSSM Higgs boson mass, in particular, those associated with non-zero top-squark mixing.