Decay widths of the neutral CP-even MSSM Higgs bosons in the Feynman-diagrammatic approach

In the Minimal Supersymmetric Standard Model (MSSM) we incorporate theHiggs-boson propagator corrections, evaluated up to two-loop order, into theprediction of $\Gamma$(h -> ff) and BR(h -> ff) for f = b, c, $\tau$. Thepropagator corrections consist of the full one-loop contribution, including theeffects of non-vanishing external momentum, and corrections of O(alpha alpha_s)at the two-loop level. The results are supplemented with the dominant one-loopQED corrections and final state QCD corrections from both gluons and gluinos.The effects of the two-loop propagator corrections and of the one-loop gluinocontributions are investigated in detail. Our results are compared with theresult obtained within the renormalization group approach. Agreement within 10is found for most parts of the MSSM parameter space.