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

TL;DR

This paper updates the ZEUS-JETS PDF fit with new ZEUS data, enhancing the precision of valence quark and gluon distributions at high and low x through inclusion of various high and low Q^2 cross-section measurements.

Contribution

It introduces the ZEUS09 PDF fit, incorporating new data to improve parton distribution functions across different kinematic regions.

Findings

Improved determination of u-valence quark at high x.

Enhanced d-valence quark accuracy at high x.

Better sea and gluon PDFs at small x.

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.