A New Study of the Polarized Parton Densities in the Nucleon

TL;DR

This paper performs a comprehensive NLO QCD analysis of polarized deep inelastic scattering data, improving the determination of polarized parton densities, especially the gluon density, and confirming consistency with theoretical expectations.

Contribution

It introduces a new NLO analysis incorporating recent experimental data, leading to more precise polarized parton density functions, particularly for the gluon.

Findings

Excellent fit to the data achieved

Improved determination of polarized gluon density

Results consistent with theoretical predictions

Abstract

We present a new next-to-leading order QCD analysis of the world data on inclusive polarized deep inelastic lepton-nucleon scattering adding to the old set of data the final SMC results, the HERMES proton and very recent SLAC/E155 deuteron data. We find an excellent fit to the data and present results for the polarized parton densities in different factorization schemes. These results are in a good agreement with what follows from the theory. We have also found that the main effect of the newly incorporated data is a better determination of the polarized gluon density.