The Longitudinal Structure Function at the Third Order
  We compute the complete third-order contributions to the coefficient functions for the longitudinal structure function F_L, thus completing the next-to-next-to-leading order (NNLO) description of unpolarized electromagnetic deep-inelastic scattering in massless perturbative QCD. Our exact results agree with determinations of low even-integer Mellin moments and of the leading small-x terms in the flavour-singlet sector. In this letter we present compact and accurate parametrizations of the results and illustrate the numerical impact of the NNLO corrections. 
S. Moch (DESY, Zeuthen), J.A.M. Vermaseren (NIKHEF, Amsterdam) and A.   Vogt (Durham Univ., IPPP)