Impact of the three-loop corrections on the QCD analysis of the deep-inelastic scattering data

We per-form the analysis of the existing inclusive deep inelastic scatterin g (DIS) data within NNLO QCD approximation. The par-ton distributions funct ions (PDFs) and the value of strong coupling constant alpha (s)(M-z) = 0.11 43 +/- 0.0013 (exp) are obtained. The sensitivity of the PDFs to the uncert ainty in the value of the NNLO corrections to the splitting functions is an alyzed. It is shown that the PDFs errors due to this uncertainty is general ly less than the experimental uncertainty in PDFs through the region of x s panned by the existing DIS data. (C) 2001 Published by Elsevier Science B.V .