Low Q^2 Structure Functions including the Longitudinal Structure Function

TL;DR

This paper presents an NLO QCD analysis of HERA data, improving parton distribution functions and including direct measurements of the longitudinal structure function F_L, testing perturbative QCD at low x.

Contribution

It provides updated parton distribution functions incorporating recent HERA data and includes direct F_L measurements to test QCD predictions at low x.

Findings

Enhanced parton distribution functions with new data

Successful measurement of F_L at x~10^{-3}

Validation of perturbative QCD in describing proton structure

Abstract

An NLO QCD analysis on the HERA combined cross sections obtained from the measurements using the data up to the year 2000 at both the H1 and ZEUS collaborations provides significantly improved parton distribution functions. In 2007, HERA successfully operated with reduced center-of-mass energies. Direct measurements of F_L were performed at x\sim10^{-3}, giving a good test of the perturbative QCD framework in describing proton structure.