Radiative corrections to the Higgs boson mass for a hierarchical stop spectrum

An effective theory approach is used to compute analytically the radiative corrections to the mass of the light Higgs boson of the Minimal Supersymmetric Standard Model when there is a hierarchy in the masses of the stops (M-(t) over bar1 much greater than M-(t) over bar2 much greater than M-top, with moderate stop mixing). The calculation includes up to two-loop leading and next-to-leading logarithmic corrections dependent on the QCD and top-Yukawa couplings, and is further completed by two-loop non-logarithmic corrections extracted from the effective potential. The results presented disagree already at two-loop-leading-log level with widely used findings of previous literature. Our formulas can be used as the starting point for a full numerical resummation of logarithmic corrections to all loops, which would be mandatory if the hierarchy between the stop masses is large. (C) 2001 Elsevier Science B.V. All rights reserved.