Measurement of the Proton Structure Function $F_2$ and the Extraction of the Gluon Density at Small $x$

TL;DR

This paper reports precise measurements of the proton structure function $F_2$ and the gluon density $xg$ at small $x$ in electron-proton collisions, confirming previous results and providing new insights into proton structure at high energies.

Contribution

It presents the first measurement of the gluon momentum density $xg$ in the range $4 imes 10^{-4} < x < 10^{-2}$ at $Q^2=20$ GeV$^2$, with improved statistics for $F_2$.

Findings

$F_2$ shows a strong rise at small $x$

First measurement of gluon density $xg$ in specified $x$ range

Results confirm previous $F_2$ measurements with higher accuracy

Abstract

In the following article we describe our measurement of the proton structure function $F_2$ and of the gluon momentum density $xg$ in $ep$ collisions with the ZEUS detector at HERA in 1993. The results for $F_2$ confirm our measurement from the previous year but with much higher statistics and show a strong rise towards small $x$. The gluon momentum density $xg$ is measured for the first time in a range from $ 4 \cdot 10^{-4} < x < 10^{-2}$ at a value of $Q^2 = 20$~GeV$^2$.