Abstract
We study the next-to-next-to-leading order (NNLO) evolution of flavour non-singlet quark densities and structure functions in massless perturbative QCD. Present information on the corresponding three-loop splitting functions is used to derive parametrizations of these quantities, including Bjorken- x dependent estimates of their residual uncertainties. Compact expressions are also provided for the exactly known, but rather involved two-loop coefficient functions. The size of the NNLO corrections and their effect on the stability under variations of the renormalization scale are investigated. The residual uncertainty of the three-loop splitting functions does not lead to appreciable effects for x>10 −2. Inclusion of the NNLO contributions reduces the main theoretical uncertainty of α s determinations from non-singlet scaling violations by more than a factor of two.
Submitted Version (
Free)
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call