First results for three-loop deep-inelastic structure functions in QCD

As a first step towards the complete calculation of deep-inelastic scattering at third order of massless perturbative QCD, we have computed the fermionic (n(f)) contributions to the flavour non-singlet structure functions in unpolarized electromagnetic scattering. We briefly discuss the approach chosen for this calculation, the problems we encountered and the status of the project. We show the results for the corresponding anomalous dimension in both Mellin-N and Bjorken-x. Together with the n(f) part of A(3), our calculation facilitates the complete determination of the threshold-resummation coefficients B-2 and D-2(DIS). The latter quality vanishes in the (MS) over bar scheme.