The NLO DGLAP extraction of $α_s$ and higher twist terms from CCFR $xF_3$ and $F_2$ structure functions data for $νN$ DIS

Abstract

We performed the detailed NLO analysis of the combined CCFR $xF_3$ and $F_2$ structure functions data and extracted the value of $α_s$, parameters of distributions and higher-twist (HT) terms using the direct solution of the DGLAP equation. The value of $α_s(M_Z)=0.1222\pm 0.0048 (exp)\pm 0.0040(theor)$ was obtained. The result has larger central value and errors, than the original result of the CCFR collaboration, in view of the incorporation into the fits of the HT terms as the free model independent parameters. The $x$-shapes of the HT contributions to $xF_3$ and $F_2$ are in agreement with the results of other model-independent extractions and are in qualitative agreement with the predictions of the infrared renormalon model. We also argue that the low $x$ CCFR data might have the defects, since their inclusion into the fits led to the following low $x$-behaviour of the gluon distribution $xG(x,9 GeV^2) \sim x^{0.092\pm 0.0073}$, in contradiction with the results of its extraction from low $x$ HERA data.