NNLO parton distributions from deep-inelastic-scattering data

Abstract

The parton distributions functions (PDFs) derived from the NNLO QCD analysis of existing light-targets deep-inelastic-scattering data are presented. The NLO and NNLO PDFs are compared in order to analyze perturbative stability of the analysis and estimate impact of the higher-order QCD corrections. The main theoretical uncertainties and experimental uncertainties in PDFs due to all sources of experimental errors in data are estimated and used to assess corresponding uncertainties in the cross sections of other hadronic processes.

Figures (3)

• Figure 1: The $1\sigma$ experimental error bands for the A02 gluon distributions obtained in the NNLO (solid lines) and the NLO (dashes) at different values of $Q$. The NNLO gluon distribution for Set 1 of MRST2001 at $Q^2=2~{\rm GeV}^2$ is given for comparison (dots).
• Figure 2: The measurements of $F_{\rm L}$ by the H1 collaboration H1 compared to the NNLO QCD predictions (solid lines: A02(leading twist+high twist); dashes: A02(leading twist); dots: MRST(leading twist)).
• Figure 3: The NNLO $W/Z$ production rates in the $\overline{p}p$ collisions at $\sqrt{s}=1.96~{\rm TeV}$ compared to the preliminary results for Run II Evans:2002wj. The area between dashes gives $1\sigma$ band uncertainty in the calculations due to theoretical and experimental uncertainties in the PDFs.