Measurement of the Proton Spin Structure Function g1p with a Pure Hydrogen Target

TL;DR

This paper reports a precise measurement of the proton spin structure function g1p(x,Q^2) using deep-inelastic scattering with a polarized hydrogen target at HERA, covering a broad kinematic range.

Contribution

It provides new experimental data on g1p(x,Q^2) with high accuracy, extending the kinematic coverage and improving understanding of proton spin structure.

Findings

Integral of g1p(x) at Q^2=2.5 GeV^2 is 0.122

Data covers 0.021<x<0.85 and 0.8<Q^2<20 GeV^2

Results enhance knowledge of proton spin contributions

Abstract

A measurement of the proton spin structure function g1p(x,Q^2) in deep-inelastic scattering is presented. The data were taken with the 27.6 GeV longitudinally polarised positron beam at HERA incident on a longitudinally polarised pure hydrogen gas target internal to the storage ring. The kinematic range is 0.021<x<0.85 and 0.8 GeV^2<Q^2<20 GeV^2. The integral Int_{0.021}^{0.85} g1p(x)dx evaluated at Q0^2 of 2.5 GeV^2 is 0.122+/-0.003(stat.)+/-0.010(syst.).