3-loop contributions to heavy flavor Wilson coefficients of neutral and charged current DIS

The present thesis presents the calculation of higher order corrections to the structure functions of deep-inelastic scattering. In particular heavy quark effects in QCD corrections are determined on the 3-loop level. In the asymptotic region Q^2 >> m^2, the heavy flavor Wilson coefficients can be represented in terms of the light flavor Wilson coefficients and the massive operator matrix elements (OMEs). New contributions to the OMEs A_{gq,Q} and A_{gg,Q} are obtained. Furthermore, methods for the computer algebraic computation of ladder diagrams are given, making use of different representations of generalized hypergeometric functions and Appell functions. Here symbolic summation techniques are applied. For the calculation of graphs with two disjoint massive cycles, these methods are altered including Mellin-Barnes integrals and properties of iterated integrals. Finally, for the process of charged current deep-inelastic scattering, the complete 2-loop corrections to the heavy flavor Wilson coefficients are constructed and given in x-space and Mellin-space. The results of the thesis are necessary for the precise determination of the parton densities (PDFs) and the strong coupling constant at 3-loop precision.