The QCD renormalization scale stability of high twists and αs in deep inelastic scattering

A sensitivity of twist-4, and alpha(s) values extracted in the NLO QCD analysis of non-singlet SLAC-BCDMS-NMC deep inelastic scattering data to the choice of QCD renormalization scale (RS) is analyzed. It is obtained that the high twist (HT) contribution to structure function F-2, is re-tuned with the change of RS. This re-tuning depends on the choice of starting QCD evolution point Q(0) and x. At Q(0) greater than or similar to 10 GeV2 the HT contribution to F-2 is re-tuned significantly at small x and weakly at large x; at small Q(0) the it exhibits approximate RS stability for all x in question. The HT contribution to F-L is RS Stable for all Q(0) and x. The RS sensitivity of alpha(s) obtained in the analysis also depends on the choice of Q(0): At large Q(0) this sensitivity is weaker than at small ones. For Q(0)(2) = 9 GeV2 the value alpha(s)( M-Z)= 0.1183 +/- 0.0021 (stat +/- syst) +/- 0.0013(RS) is obtained. Explanation of those effects based on the analysis of the QCD evolution equations properties is given and connection with the higher order QCD corrections is discussed. (C) 2000 Elsevier Science B.V. All rights reserved.