A QCD analysis of ZEUS data including DIS inclusive cross sections with longitudinally polarised leptons and data run at lower proton beam energies

Abstract

New ZEUS data are added into the NLO QCD analysis of the ZEUS-JETS PDF fit. The addition of high-$Q^2$ NC and CC $e^{-}p$ inclusive cross-section data improves the determination of the $u$-valence quark at high $x$. The addition of high-$Q^2$ CC $e^{+}p$ inclusive cross-section data improves the determination of the $d$-valence quark at high $x$. The addition of lower-$Q^2$ NC $e^{+}p$ inclusive cross-section data, run at three different proton beam energies, improves the determination of the sea and gluon PDFs at small $x$. The new PDF fit is called the ZEUS09 PDF fit.

Comments: Invited talk on behalf of the ZEUS Collaboration at DIS 2009, The 17th International Workshop on Deep Inelastic Scattering, Madrid, April 2009. % pages, 6 figures