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

A sensitivity of twist-4 and αs 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 F2, is re-tuned with the change of RS. This re-tuning depends on the choice of starting QCD evolution point Q0 and x. At Q0≳10 GeV2 the HT contribution to F2 is re-tuned significantly at small x and weakly at large x; at small Q0 the it exhibits approximate RS stability for all x in question. The HT contribution to FL is RS stable for all Q0 and x. The RS sensitivity of αs obtained in the analysis also depends on the choice of Q0: At large Q0 this sensitivity is weaker than at small ones. For Q02=9 GeV2 the value αsMZ=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.