Non-singlet QCD analysis of deep inelastic world data at O(αs3)

Abstract A non-singlet QCD analysis of the structure function F 2 ( x , q 2 ) in LO, NLO, NNLO and N 3 LO is performed based on the world data for charged lepton scattering. We determine the valence quark parton densities and present their parameterization and that of the correlated errors in a wide range of x and Q 2 . In the analysis we determined the QCD-scale Λ QCD , N f = 4 MS ¯ = 265 ± 27 MeV ( NLO ) , 226 ± 25 MeV ( NNLO ) , 234 ± 26 MeV ( N 3 LO ) , with a remainder uncertainty of ± 2 MeV for the yet unknown 4-loop anomalous dimension, corresponding to α s ( M Z 2 ) = 0.1148 ± 0.0019 NLO , 0.1134 −0.0021 +0.0019 NNLO , 0.1141 −0.0022 +0.0020 N 3 LO . A comparison is performed to other determinations of the QCD scale and α s ( M Z 2 ) in deeply inelastic scattering. The higher twist contributions of F 2 p ( x , Q 2 ) and F 2 d ( x , Q 2 ) are extracted in the large x region, subtracting the twist-2 contributions obtained in the NLO, NNLO and N 3 LO analysis.