Non--Singlet QCD Analysis of Deep Inelastic World Data at \boldmath $O(α_s^3)$

Johannes Blümlein; Helmut Böttcher; Alberto Guffanti

Paper

Non--Singlet QCD Analysis of Deep Inelastic World Data at \boldmath $O(α_s^3)$

Abstract

A non--singlet QCD analysis of the structure function

in LO, NLO, NNLO and N

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

and

. In the analysis we determined the QCD--scale

, with a remainder uncertainty of

for the yet unknown 4--loop anomalous dimension, corresponding to

. A comparison is performed to other determinations of the QCD scale and

in deeply inelastic scattering. The higher twist contributions of

and

are extracted in the large

region, subtracting the twist--2 contributions obtained in the NLO, NNLO and N

LO analysis.