Parton distribution functions from the precise NNLO QCD fit

Abstract

We report the parton distribution functions (PDFs) determined from the NNLO QCD analysis of the world inclusive DIS data with account of the precise NNLO QCD corrections to the evolution equations kernel. The value of strong coupling constant α_s^{NNLO}(M_Z)=0.1141(14), in fair agreement with one obtained using the earlier approximate NNLO kernel by van Neerven-Vogt. The intermediate bosons rates calculated in the NNLO using obtained PDFs are in agreement to the latest Run II results.

Figures (2)

• Figure 1: The gluon distributions obtained in the different variants of the analysis (solid: the fit with the exact NNLO evolution; dashes: the fit with approximate NNLO evolution; dots: the approximate NNLO gluons evolved with the exact NNLO kernel; dashed-dots: the NLO fit).
• Figure 2: The NNLO calculation of the $W/Z$ rates for Run II at Fermilab compared to the data. The dotted lines give the uncertainty in calulations due to errors in PDFs; the error bars of the data points give the total error including one due to the luminosity uncertainty. The branching ratios of the $W/Z$ leptonic decays $BR(W \rightarrow l\nu)=0.107$ and $BR(Z \rightarrow ll)=0.034$ were applied.