# TTP02-22 Non-Singlet Structure Functions at Three Loops: Fermionic Contributions

TTP02-22 Non-Singlet Structure Functions at Three Loops: Fermionic Contributions

TTP02-22 Non-Singlet Structure Functions at Three Loops: Fermionic Contributions

We compute the fermionic (n_f) contributions to the flavour non-singlet structure functions in unpolarized electromagnetic deep-inelastic scattering at third order of massless

      perturbative QCD. Complete results are presented for the

corresponding nf-parts of the three-loop anomalous dimension and the three-loop coefficient functions for the structure

      functions F_2 and F_L. Our results agree with all partial and

approximate results available in the literature. The present calculation also facilitates a complete determination of the

      threshold-resummation parameters B_2 and D_2^DIS of which only the

sum was known so far, thus completing the information required for the next-to-next-to-leading logarithmic

      resummation. We find that D_2^DIS vanishes in the MSbar scheme.
 S. Moch, J.A.M. Vermaseren and A. Vogt Nucl.Phys. B646 181-200 2002 PDF PostScript arXiv