Parton distributions from deep-inelastic-scattering data

Abstract

We perform the analysis of existing light-targets deep-inelastic-scattering (DIS) data in the leading-order (LO), next-to-leading-order (NLO), and next-to-next-to-leading-order (NNLO) QCD approximations and extract PDFs simultaneously with the value of the strong coupling constant $\alpha_s$ and the high-twist contribution to the structure functions. The main theoretical uncertainties and experimental uncertainties due to all sources of experimental errors in data are estimated, the latter generally dominate for the obtained PDFs. The uncertainty in Higgs boson production cross section due to errors in PDFs is $\sim 2$% for the LHC and varies from 2% to 10% for the Fermilab collider under variation of the Higgs boson mass from $100 {\rm GeV}$ to $300 {\rm GeV}$. For the $W$-boson production cross section the uncertainty is $\sim 2$% for the both colliders. The value of $\alpha^{\rm NNLO}_{\rm s}(M_{\rm Z})=0.1143\pm 0.0014({\rm exp.})$ is obtained, while the high-twist terms do not vanish up to the NNLO as required by comparison to data.