Structure Functions at Low x and Q2 at ZEUS

TL;DR

This paper reports measurements of the proton structure function F2 at very low Q2 and x values using ZEUS data, extending the kinematic range and improving accuracy with new detector components.

Contribution

First measurement of F2 at low Q2 and x using ZEUS data with enhanced detector components for better accuracy and extended kinematic coverage.

Findings

Extended the accessible Q2 range down to 0.015 GeV^2.

Improved background suppression and systematic uncertainties.

Provided new data for proton structure at low x and Q2.

Abstract

Using 3.9 $pb^{-1}$ of data from ep $\ra$ eX interactions recorded using the ZEUS detector in 1997,the proton structure function, F$_2$, has been measured in the range 0.015 GeV$^2$ $<$ Q$^2 <$ 0.65 GeV$^2$ and $6 \times 10^{-7} < x < 1 \times 10^{-3}$. The analysis is based on data taken incorporating new detector components. Compared with the previous analysis, these components allow improved background suppression and better control of systematic uncertainties, extending the accessible kinematic region towards lower Q$^2$.