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 scattering (DIS) data within NNLO QCD approximation. The par-ton distributions functions (PDFs) and the value of strong coupling constant alpha (s)(M-z) = 0.1143 +/- 0.0013 (exp) are obtained. The sensitivity of the PDFs to the uncertainty in the value of the NNLO corrections to the splitting functions is analyzed. It is shown that the PDFs errors due to this uncertainty is generally less than the experimental uncertainty in PDFs through the region of x spanned by the existing DIS data. (C) 2001 Published by Elsevier Science B.V.