Structure Function Measurements at HERA

TL;DR

This paper presents combined structure function measurements from H1 and ZEUS at HERA, covering a wide kinematic range, and introduces the HERAPDF1.0 parton density functions along with new F_L measurements.

Contribution

It provides the first combined analysis of HERA data leading to the HERAPDF1.0 set and includes new direct F_L measurements using dedicated low energy runs.

Findings

Combined data reduce experimental uncertainties.

HERAPDF1.0 provides improved parton density functions.

New F_L measurements enhance understanding of proton structure.

Abstract

Recent structure function results from the H1 and ZEUS Collaborations are presented. The data cover a wide kinematic range of squared four-momentum transfers Q^2, from 0.2 GeV^2 to 30000 GeV^2, and Bjorken x between 5*10^-6 and 0.65. Data from both experiments have been combined, leading to significantly reduced experimental uncertainties. The combined measurements are analysed using a NLO QCD fit, and a set of parton density functions, HERAPDF1.0, is extracted. New direct measurements of the structure function F_L, making use of dedicated low energy runs of the HERA machine, are also presented.