FeynHiggsFast: a program for a fast calculation of masses and mixing angles in the Higgs Sector of the MSSM

FeynHiggsFast is a Fortran code for the calculation of the masses and themixing angle of the neutral CP-even Higgs bosons in the MSSM up to two-looporder. It is based on a compact analytical approximation formula of thecomplete diagrammatic one-loop and the dominant two-loop contributions. At theone-loop level a leading logarithmic result is used, taking into account allsectors of the MSSM. At the two-loop level at O(alpha alpha_s) the leadinglogarithmic and non-logarithmic contributions are taken into account. Theapproximation formula is valid for arbitrary choices of the parameters in theHiggs sector of the model. Comparing its quality to the full diagrammaticresult, we find agreement better than 2 GeV for most parts of the MSSMparameter space.