Higher-order Results for Precision Observables in the Standard Model and the MSSM
Recent higher-order results for precision observables in the Standard Model (SM) and the Minimal Supersymmetric Standard Model (MSSM) and for the neutral CP-even Higgs-boson masses of the MSSM are summarized. Furthermore a brief discussion of the technical aspects of evaluating higher-order corrections in the electroweak theory is given. In the SM, results for the Higgs-mass dependence of the precision observables are analyzed. The exact two-loop results for the Higgs-mass dependence of the fermionic contributions are compared with the results of an expansion in the top-quark mass up to next-to-leading order. In the MSSM, results for the leading two-loop contributions to the precision observables and to the masses of the neutral CP-even Higgs bosons are discussed. The latter are compared with results obtained by renormalization group calculations.