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

Abstract

A sensitivity of twist-4 and $α_s$ values extracted in the NLO QCD analysis of nonsinglet SLAC-BCDMS-NMC deep inelastic scattering data to the choice of QCD renormalization scale (RS) is analysed. It is obtained that the high twist (HT) contribution to structure function $F_2$, is retuned with the change of RS. This retuning depends on the choice of starting QCD evolution point $Q_0$ and x. At $Q_0 > 10 GeV^2$ the HT contribution to $F_2$ is retuned at small $x$ and almost not retuned at large $x$; at small $Q_0$ 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 $α_s$ also depends on the choice of $Q_0$: at large $Q_0$ this sensitivity is weaker, than at small one. For $Q_0^2=9 GeV^2$ the value $α_s(M_Z)=0.1183\pm0.0021(stat+syst)\pm0.0013(RS)$ is obtained. Connection with the higher order QCD corrections is discussed.